Complete newbie requesting help with first octopus setup!


Hi everyone!

I've been lurking around here for a little while but am completely green on this subject, handle with care! :smile:

I recently became totally fascinated by octopuses, biologically and socially, and after a while got my heart set on getting one. I have of course read around the subject in as much detail as I can, and I understand that it is challenging and that an octopus is fairly high maintenance and am aware that ownership is not to be taken lightly. I have kept lizards in the past (leopard geckos, green iguanas and tegus), so I know something about the demands of exotic animals in the home, however this is all new as I have never ever kept any kind of marine life, not even a goldfish. So I've really thrown myself in at the deep end. I know a lot of you will probably just tell me to start with a simple saltwater aquarium but I really just want an octopus, and I think and hope that I can follow instructions fairly well. I work at home and don't have the mobility to go out much so I will have plenty of time to interact and look after him (or her).

So I've started by ordering a couple of books from Amazon that seemed to come recommended (Octopus: The Intelligent Invertebrate, and Octopuses and Cuttlefish for the Home Aquarium), and downloaded/watched The Ultimate Guide: Octopus after reading around tonmo and some other sites. I've made a basic list of everything I think I will need and would like it if anyone can give me any feedback, corrections etc. Try to imagine that my house is completely 'empty' when it comes to marine equipment, even things like buckets. I tried to make a comprehensive list with this in mind.

I selected O. bimac as the species since I'm on a fairly tight budget and can't afford a large tank (I live in Norway and they are extremely expensive, even a basic 50 gallon (190 liter) tank is over $600, so I have to be frugal). This is what I came up with:

- Aquarium - at least 190 liters (50 gallons) - not copper-based treatment as this will kill the octopus
- Mechanical filters, need to remove ammonia, nitrate and nitrate, chemical filter will kill octopus
- Flourescent light, not excessively bright
- Timer for wall socket - 8-10 hours of daylight for octopus
- Hydrometer (swing arm) to test salinity
- Synthetic sea salt - one cup per 2 gallons - salinity measured with hydrometer, 1.023 - 1.026 for octopus
- Protein skimmer - must be rated for 3 times the size of the tank
- Carbon
- Large buckets for the water
- Live rocks (rocks with bacteria growing on) to help absorb waste from the octopus
- Test kit: need to test pH, amoonia, nitrate, nitrate, gravity/salinity (with hydrometer), oxygen level
- Copper tester - copper is fatal to octopuses and must have a level of zero
- Heater / chiller - octopus requires lower 70s F (70-74 is 21-23 C)
- Aquarium substrate - do not use coral sand as it hurts octopus skin; fine 'aquarium' sand, depth 1 inch (2.5cm)
- TWP / RO/DI filter - do we need this in Norway?
- Air pump with wooden diffusers to agitate surface layer of water
- PVC pipes to entertain octopus
- Hosepipe or some other tool to siphon the water when changing it

So here are some questions that will unfortunately sound naive and dumb but any guidance would be great. I am also not good at DIY so if anything requires this, please try to keep it simple and dumb :)

What is the difference between what is advertised as a 'freshwater' and 'saltwater' aquarium? The prices of saltwater aquariums here appear to be as much as 3 times higher. Can you not just use a freshwater aquarium that has never had any water in it and not been treated with copper?

How many liters (or gallons) per hour does the pump need to be?

Should I use a Wet/Dry filter / bioballs?

When changing the water, do I take the octopus out? Is it ok to put him in a large bucket?

How do you stop the octopus burning its arms on the heater?

How do you secure the rocks to the tank so that they don't fall on the octopus if he is playing around them? Same question for plastic pipes/toys

If you have to use a layer of glass on top of the aquarium or some other tight-fitting lid, how do you connect the accessories to the intakes on top of the aquarium?

What's the best way to secure the lid?

What's the best way to siphon water out of the tank when changing it?

When handling the octopus, what is the best way to hold it / pick it up without hurting it?

Is it better to get a male or female octopus? I was thinking mostly about all the eggs the female would lay at the end of her life being a nuisance or maybe even depressing.

Where to keep it: I basically have two choices, the back wall of my home office or the side wall of my living room. Either way the octopus will see a lot of me, and it would definitely be better aesthetically to have it in the living room, but I also have my home cinema in there; I know octopuses are thought to be deaf but will the vibrations stress him out or does it not matter? The office is quiet.

Aside from that, I wrote down these reminders which I hope are ok:

- Cycle tank for 3 months before adding octopus
- Ensure plenty of hiding places for octopus to avoid stress
- Do not use undergravel filter as octopus will dig it up
- Cannot use tap water as contains chemicals that are toxic to octopus - RO/DI (reverse osmosis deionized water)
- Change 25% of the water 1-2 times per week; do not add extra salt
- Food: frozen shrimp but preferably live crustaceans, mussels so that octopus can hunt for food

Is there anything I missed or anything general about keeping an aquarium that I would be totally unaware of from reading up on it? Finding an octopus or an expert in Norway is rather difficult but on Wednesday I am hopefully going to take a trip to the capital Oslo to the largest aquarium shop. I gave them a ring today and they have an octopus expert there, luckily.




Pygmy Octopus
Hi! I'm new here too and I don't have an octopus yet (or even marine aquarium), but I'm pretty good with freshwater, so I can talk about the universal stuff. Read about the nitrogen cycle (if you haven't already). Knowing this like the back of your hand will help A LOT. It will also help you understand why you need a lengthy cycling period, why people will say a certain amount of space in need for certain animals (besides the obvious size issue) and what types of filtration to use.

You don't have to remove your octopus when you do water changes, I imagine that might even be unnecessarily stressful. Just watch yourself and don't suck it up with your siphon :grin:


Colossal Squid
Staff member
:welcome: to TONMO. It sounds like you've done quite a bit of reading already. I'm sure the experienced octo-keepers will chime in shortly, but I can toss out a few things to think about... first, you should seriously consider having a sump for your tank, and putting the heater, filtration, and so forth in there. It would add water volume, keep equipment away from the octopus, and help to octo-proof your tank. Second, you probably don't want to plan for a bimac at this point. The captive breeders of bimacs have all gone out of business, and we've found that strictly speaking, collection of bimacs for sale as pets is against California fish & game regulations, so the only pet bimacs available are ones the people collect for themselves (not for resale). You should probably consult with the octopus expert in Oslo to find out what species are commonly available there, and try to choose a tank and temperature that can handle those species.


Staff member
NOTE: I apologize for repeating much of Monty's post in my first paragraph - saw it after writing my tomb - but will leave the paragraph as the information is worth repeating.


Before you start it would be wise to do some research on a source for octos. It is almost impossible to get bimacs in the US unless you catch them yourself so I expect they will not be available at all in Norway. The two most likely animals you will find will be the deadly blue ring from Australia and the vulgaris (or common octopus) that is native to all oceans (though slightly different depending on local). The blue ring is not an animal for an inexperienced aquarist or an experienced aquarist that has not already handled a number of other venemous animals. The vulgaris is a great animal but will need a much larger aquarium than your budget allows. If you find a source that says it can get you another species, post what is known or where it comes from and we can usually give some guidance. Outside of the two I mentioned, typically exported are the Indonesian aculeatus (or other members of the Abdopus family) and a small macropus. Both are suitable for a 50 gallon aquarium. The aculeatus, unfortunately is usually and adult and typically live only two to three months before naturally expiring. The little macropuses we have seen are very friendly and interactive if you are up very late at night. Go to the Forums->Journals section and click on the List of Our Octopuses 2010 (or other years) sticky at the top of the forum. The list shows the species we are seeing (mostly in the US) and links to the journals of each octopus. Reading through some of the journals will help you get an idea of what keeping an octopus entails. We currently have one accidental vulgaris that might be of particular interest :wink: but do note that the keeper had to upgrade the tank and we are hoping she won't out grow her 130 gallon tank.

The difference between saltwater and freshwater tanks:
A saltwater aquarium will be set up with an overflow box and holes drilled in the bottom or sides to allow water to drain to and return from a secondary tank below the primary aquarium. The secondary tank is called a sump. In this kind of setup all the filter equipment is placed in the lower tank, making it ideal for an octopus because you can easily cover the tank. People use freshwater tanks for saltwater as there is no difference in the physical tank glass or sealant but they will either DIY the overflow or use a canister filter and no sump. We do have people that use a canister and work around the skimmer and hoses with tape and various other DIY ideas to close exit points but I highly recommend using a sump and avoiding the top difficulties and canister maintenance.

If your living room is carpeted or has other flooring that would be water sensitive, you need to think twice about putting the aquarium in that room. You will be removing and replacing about 5 gallons of water every week or every other week and the floor WILL get wet.

You do seem a bit confused about water changes and water top offs (this may be a translation issue more than confusion). You will need to put new fresh (not salt) water into the tank to replace water that evaporates (we do it daily but frequency is highly dependent on evaporation rate. You will do water changes 30% over a month period (not 25% twice a week). Some people prefer to do them once a month where others will do 10% weekly. This involves removing water from the tank and replacing it with new SALTWATER. When water evaporates, the salt does not exit with the water so you replace only the water. When you remove water the salt is also removed so it is necessary to replace it with saltwater.

Once you are sure you can find an octopus, consider waiting 6 months instead of 3 after you have set up the tank and use that time to get a better feel for your maintenance routines (you will not have to do too much in the beginning) and learning the saltwater envrionment. You will want a clean up crew in the tank so you can learn much with feeding and watching these critters. I am particularly fond of the brittle stars (I am not much of a fish person) and some of them will learn to be hand fed relatively easily.

You will not remove the octopus from the tank for any reason other than to transfer it to another aquarium and in that case, you should not need to handle it. Should it escape and you need to pick it up, I have found that placing your wrists together and then putting your joined hands over the octopus mantle and flipping the octopus over so that its beak is pointing toward the ceiling is a safe way to handle them without hurting either party.

For siphoning water, any hose works but there is an aquarium siphon you can buy in a fish store that has a self priming pump (squeeze ball) that is useful and helps to not have to swallow saltwater (most of the time).

Glass is not the most common material for a top and could only be used where it does not need to go around wires or other equipment. I use acrylic and other have used screen material. Unfortunately, you are going to have to do a little DIY if you can't find something already set up. Using a sump minimizes the problem but does not eliminate it.

Again, a sump eliminates the problem with a heater (you probably won't need a chiller). It is very difficult to safely put a heater in a tank with an octopus as they do not understand heat and can burn themselves. I recommend a metal heater and not a glass unit even if you do have a sump.


D, you are so patient and concise. :smile:
The comments below pertain to SW aquariums in general.
I will typically advise newcomers to start a simple (ya, I know) reef tank, and see how they do keeping it for a year.
Also, a ton of money can be saved, and nearly assured success by finding an honest mentor - maybe through your local reef / sw aquarist club. Knowledge and sources for used equipment are extremely valuable.
In contrast, I have seen folks "go it alone" and many and end up chasing their tail (trying to figure out problems they're having) and end up so frustrated that they jump out of the hobby just as fast as they jumped in. Come to think of it, these same people rarely take the good advise given to them by experienced aquarists anyway...


Thank you all for the very helpful responses, and for the corrections :smile: I realised that the salt stays when the water evaporates but I hadn't realised it evaporated so fast that it had to be topped up daily with freshwater.

I will not buy a blue ring octopus, Tonmo has taught me that already, so don't worry about that :)

Reading about the nitrogen cycle clarified a lot for me about cycling the tank, I am not sure what animals to put in it at first, I don't think I am much of a fish person either so I will have a look in my local pet store and see what other critters they have that might be suitable.

I didn't realise the bimac wasn't available; it is really a vulgaris that I originally saw that sparked my interest in the subject but I know I can't afford a large enough setup for one, so I mostly settled on the bimac for size reasons. I had already started reading the List of Octopuses 2010 journals so I will keep doing that; the aquarium I'm planning to visit is one of the only places you can get an octopus in Norway and they only have them in from time to time - mostly if someone asks for one I think because this is a very small country and they don't want to have them in stock if nobody will buy it before it dies - so I will ask them what species they get and report back here :)

As for the time line I am impatient but I know I have to be patient for this, and my budget may mean that I have to practice with the water conditions for 6 months before I've gathered up all the other things I'll need to look after an octopus anyway. I guess I'll see how much trouble I have keeping the water quality under control properly. If I haven't got a good grasp of it after 3 months then of course I will not put an octopus in there.

What is the overflow box on the saltwater aquarium used for? (translation difficulties perhaps :P)

My living room has a rug but that can be moved without trouble, the floor is made of hardwood. The office floor is vinyl, so I guess those are both ok, I've spilled coffee on them enough times hehe. But will the vibrations from say watching a loud movie upset the octopus? If that is the case I will put him in the office.

I've made a note to make sure the heater is metal and not glass.

In terms of setting up the aquarium before the octopus comes, am I right in thinking I don't need a protein skimmer at this stage and can buy one later? I just need to get together the very basics of what I need at first, I can't afford to buy everything at once unfortunately. Is there anything else I don't need when there is no octopus in the tank?

Regarding clubs, sources etc. Norway is basically a country with a large land mass and a tiny number of people. I live in the 5th largest town and it has a population of 93,000, there are almost no clubs of any kind for any hobby unless you live in Oslo (with a population of 500,000 - an 1/8th of the total population). Most of us don't drive cars either because the towns are very compact; I have been very lucky to rope my ex-boyfriend into driving me to the aquarium (he thinks I have gone crazy) and today he has offered to do a little DIY if needed and to drive me across most of the country if I can find some good used equipment online, which was very nice of him. With that in mind I have looked over our only national trading site '' (it's like an online classified ads site for all kinds of goods) and seen some well-priced saltwater aquariums with various accessories. So with that in mind, before we take a 15 hour roadtrip somewhere, what sort of things should I be watching out for (good and bad) if I buy a pre-owned aquarium?

Thanks again!



Staff member
AVOID any tank that has used copper medication. MOST saltwater CORAL tanks will not have been exposed but ASK.

Yes, you can buy the skimmer later in the process.

You can find interesting clean-up crew critters that are more interesting than fish (IMO), will be the first things you add to your tank and serve a useful purpose. Pencil urchins (other urchins are a potential danger to the octo skin but some keep the pin cushions as well, avoid the long spined or rocks), serpent starfish, brittle starfish, hermit crabs and snails can be interesting. I particularly like the serpent stars and have a number of them in each of my tanks. AVOID GREEN brittle stars but most other serpent/brittles are great (my green is great too but he has to live by himself as they are aggressive after they reach a certain size). There are some very interesting shrimp that are colorful and/or have interesting behavior but they will become octo food. Sometimes peppermint shrimp will learn fast enough to avoid the octopus but you can't count on it. You can eventually add a few simple, easy to keep polyps or mushrooms to add a little color and not add to the difficulty of maintaining the tank.

Overflow box: The best set up for an octopus (arguably for any saltwater setup) is to use a sump (the second tank underneath the primary tank I mention above). To get the water from the top tank to the bottom tank, you want to be sure that if the power goes off (among other things, like drawing water from a larger area) the large upper tank won't drain into the small bottom tank. The common way to accomplish this is to place sealed box inside the big tank and place a fitting (called a bulkhead) through the box and through the tank (or sometimes at the bottom of the tank, depending upon the set up). This sealed box (or overflow box) will have grooves cut at the top to allow tank water to enter but will stop taking water if the level is below the grooves. When you first fill your tank, leave the sump empty, turn off the tank and see how much water drains with the power off, measure the depth and mark it from the TOP of the sump tank then do not fill your sump past this mark. If the tank is bottom drilled (the hole is in the bottom of the tank), it is wise to put a pipe in the fitting at a length a little lower than the bottom of the grooves. This is not as efficient for cleaning but will avoid disaster if the overflow box should leak and the power is off for a long period of time. Side drilled tanks are not quite as worrisome if the hole is not too far down the tank wall and a stand pipe is not usually necessary.

Only recently did we discover that octopuses can hear at all and most of its range is outside that of the human ear but I vote for the vinyl floor because it is very hard not to have standing saltwater where you don't easily see it. The noise is not a problem unless there is excessive vibration (like a lot of bass). One of mine would be really unhappy if I did laundry during his sleeping time as the washer and dryer were on the other side of the wall and the vibration would make him pace the tank when he should have been sleeping. He did not seem to have a problem with it during the day.


Thank you D, that was another highly informative post and much appreciated! The overflow box clarification was great, and the list of clean-up crews, I've never really looked at the stars, I will take a look on Wednesday, I'm sure I'll like the crabs though. Is it safe to leave them in afterwards and just let the octopus eat them or is that a bad idea?

I went and traded in half of my prized collection of video games today (my other hobby), it was heartbreaking but I amassed a quick $750 due to the good prices of second-hand stuff in Norway so that will go excellently towards the costs.

I located and walked to 3 of the 4 pet stores in my town today (the 4th is not in walking distance and even saying that I walked several hours today). There are no sources of live food that an octopus can eat, but frozen shrimp is extremely cheap as we live by the ocean.

Ultimately, I was the one telling them what an octopus needs to my limited knowledge, but eventually I found an extremely helpful saltwater aquarist, he explained many things well and was able to grasp exactly what I needed when I explained some of the problems of keeping an octopus. I took a laundry list of items and we went through it all, he was also good enough to recommend cheaper places for certain items, put me in touch with a gentleman who imports octopuses from Indonesia (so I will write to him and ask what species he has), and another gentleman selling a tank that has been converted with an overflow and sump intakes for a very low price. So, plenty of leads to investigate. I will report back later!



Colossal Squid
Staff member

If u live near the water then there must be people that fish. Check the local fishing stores and see what live bait for fishing is available. They may have some sort of live shrimp or crabs. That's what i do.


Okay I have just seen this by coincidence on the Norwegian salt water forum that has been recommended to me by a couple of people:

I will translate it:

"Complete Rio 180 [just under 50 gallons] to be sold with sump and a 150WHQI 2x24W light

Comes with BM NAC6A protein skimmer, Eheim 1060 return pump, 60 litre +/- sump, wave maker, air pumps etc.

Comes with live rock, corals, (something I don't know in English) and one fish."

The price is about 1/5th of the same thing new and less than half what the other sellers are offering for their used aquariums, it is also only a 15 minute drive from here which is very unusual. The seller states at the bottom that it is cheap because he needs to get rid of it quickly.

Would this be suitable if I cleaned it out, put fine sand in and a more powerful protein skimmer?


Staff member
It is certainly worth looking at. Be sure he never used copper medication for the fish but there is a good chance he has not because of the corals. Be sure it holds water (it sounds like it is a function system though so leaks should be obvious). From the photos, I would say you have yourself a tank :wink:


Thanks D, ok I have written to the seller. Am I right in thinking these will be the immediate supplies I need to go out and grab if I come home with the aquarium after looking at it:

Synthetic sea salt
Filter material
Small net
Algae scraper
Test kit
RO/DI filter

Is there anything that can be delayed (especially the RO/DI filter as it's expensive)? Or do I need all of that immediately? Anything I missed?



Staff member
Unfortunately the RO/DI and figuring out how you will set it up needs to be at the top of your list and should not use any other kind of water (distilled is OK). IT needs to be attached to a water supply and have a place for the rejected water to drain. If you buy the existing tank, you can draw off the water (so your buckets need to accomodate the 180 L and have TOPS) and refill the tank with it but you will still need fresh top off water immediately for evaporation loss as well as to be able to fill the tank with new saltwater (you will likely not bring all of it home). It is not just that the water evaporates but as it does, the water gets saltier so to keep a balanced system you need to top it off regularly or the salinity will change. I don't know what the availability of distilled water is and its cost so you would have to weigh that against the expense of the RO/DI unit for your immediate expenses. These units make filtered water VERY slowly so it will not be like you can turn on the tap and fill up a bucket. It will take a day to fill a 20 gallon container.

Check the prices for your salt (again you may want to see if the seller is including some that he has left). Typically it is better to go ahead and buy the larger quantity up front but the outlay is pricey.

If you can get the test strips (we have combination strips for PH, nitrate and nitrite and a solo strip for ammonia) these are far more convenient than the reagent kits that usually have expired reagents. They MAY not be as accurate (my dual tests say they are since both require color determination by the viewer) but they are satisfactory for the home aquarist and take seconds, not hours to test the water.

You WILL want to empty, clean and replace the filter material in the filter. Find out what he is currently using. It will likely be charcoal and a fiber filter media. I find it far easier to put bag of charcoal in a filter sock and place it in the sump under the overflow hose than deal with the canister but, in this case the canister is used as a return pump (I use a plain pump for return). If you consider filtering with a filter sock in the sump, you can eliminate the filtration in the canister or simply add more charcoal without the polyfilter material. Again, I am not sure what is available to you. Relooking at the photos though, he may already have a filter sock and bag of carbon at the return. If this IS the case, he may not be running any filter media in the canister so it is best to ask before you buy anything for it.

It is going to be heavy work and a bit daunting for you to set this up by yourself. You will need at least one person to help carry and set up (the tank is HEAVY) but if you can find someone (you are very good at this I note) that knows something about a saltwater system that could help you put it back together, I would suggest offering them dinner for a nights work. If not, then take lots and lots of pictures (you might do this anyway) so that you can see where everything goes.

You will want to be sure to keep the rock WET the entire time. If it will be out of the tank for more than a few hours, then you should circulate water around it until it can go back into the tank.

I am not sure what food you should purchase. If he has a clean up crew in the tank, he will likely give you whatever he has left that he is feeding it, the corals and the lone fish. I would hold off buying anything until you have the tank set up.

See if the setup comes with a thermometer and hydrometer. If he is getting rid of everything, these are likely included. If not the inexpensive stick on thermometers are fine but do not get a glass hydrometer. The floating glass kind are too easily broken and almost impossible to read. The least expensive are the plastic ones that have a swing arm. You fill them with water and then place them on a level surface to read. ALWAYS rinse it out with fresh water or you will get improper readings due to the salt build up in the unit.

I would consider rinsing the bottom substrate (sand) with saltwater as you place it back into the tank if you remove it to do the move. Removing it will lighten the tank considerably but will disrupt the sand bed and is likely to release toxins. IMO removing, rinsing (SALTWATER rinse) and replacing is best even if you don't have to unless you replace it with new substrate. This is easier said than done and I usually use a plastic colander (like you use to drain spaghetti or other noodles but a new one, not one you use for food) to help with this task but it is still time consuming.


Right, all good stuff and thoroughly informative once again! :)

Here are the naive questions I have arising then. I really want to make sure I don't screw anything up and get myself into a mess so I'm going to ask even the most obvious things. I'm a software developer so this is really not my normal forte :smile:

- Filter sock. Is this something special? Does it come with the carbon?

- Circulating water round the rock: freshwater or saltwater? Put them in a bucket?

- Food. How long can I leave it before the coral and fish will start to suffer, or is it highly dependent on species?

- Hydrometer. There were refractometers in one of the shops I went to yesterday, they were about 50% more expensive than the swing arm hydrometers. What would you recommend? Does the refractometer need any maintenance like the cleaning you mentioned of the swing arm hydrometer?

- I'm not sure what a colander is, is that like the thing you use to drain the water out of pasta but with much finer holes, like a sieve? Can you give the exact process of rinsing the sand so I don't mess it up please :smile:

On the rest: I have someone who can help me carry the tank; fortunately I checked the prices of the other stuff mentioned yesterday with the saltwater expert, the salt is fairly cheap, the RO/DI filter will likely quickly pay for itself compared to the cost of distilled water, but I get paid on 1st so it can probably go with distilled water for a few days if need be. I couldn't find any combo test strips, only separate ones for pH, ammonia, nitrite, nitrate and copper. Does the oxygen level need to be tested somehow? Do you just dunk the strips in the water for a few moments then look at the colour?

I think that's it :)


And three more questions:

1. RO/DI filter. Does it have any gravitational requirements, ie. it has to go below the level of the connector coming out of the tap? If I put the bucket in my sink I think the tube will be in a sideways S shape.

2. Replacing substrate - will I not need to replace it anyway with fine sand to avoid the eventual octopus from hurting itself?

3. What is the difference between distilled water and RO/DI water? We get distilled water out of our taps, it is exactly the same as what is in the bottles you can buy.

Starting to get quite daunted now as I realise the complexity of the task for a newbie and why the sites tell you not to start with an octopus hehe. I hope I will not make too many mistakes, I guess it will be rather trial and error at first, but I'm usually ok with following instructions. I have made detailed notes on my computer (some from this thread) to print out about what to ask about, the equipment needed, what it's for, what the levels should be, some of the maintenance processes and the step by step instructions for setting everything up so that I can refer to everything in one place. Trying to be organised!


Staff member
? Filter sock. Is this something special? Does it come with the carbon?
It looks just about as it sounds. It is a washable fiber material bag with a collar. I place a mesh bag of charcoal in mine and it looks like the current owner does something similar. I is a nice, simple and easy to clean filter system for particulate matter.

?Circulating water round the rock: freshwater or saltwater? Put them in a bucket?
Never expose live rock to freshwater if you want it to remain "live" rock. Fresh water will kill all the bacteria that you buy the rock for.

?Food. How long can I leave it before the coral and fish will start to suffer, or is it highly dependent on species?
We feed our tanks daily (with one day of no food) but others feed every other day. My suggestion for waiting is to see what will come with the tank but you will have to have something quickly.

?Hydrometer. There were refractometers in one of the shops I went to yesterday, they were about 50% more expensive than the swing arm hydrometers. What would you recommend? Does the refractometer need any maintenance like the cleaning you mentioned of the swing arm hydrometer?
A refractometer is considered the best way to monitor your salt. However, you will have to calibrate it and keep it calibrated (not required often). You should be able to buy the calibration fluid in the same store. Most aquarists would highly prefer the refractometer.

?I'm not sure what a colander is, is that like the thing you use to drain the water out of pasta but with much finer holes, like a sieve? Can you give the exact process of rinsing the sand so I don't mess it up please :smile:
Yes (and why I mentioned noodles since the word might be strange) but you will not want finer holes I don't think. The holes are to let the water out, not the sand and it packs in pretty tightly. A sieve might clog more easily and we just want a simple rinse.

? RO/DI filter. Does it have any gravitational requirements, ie. it has to go below the level of the connector coming out of the tap? If I put the bucket in my sink I think the tube will be in a sideways S shape.
It runs from your water pressure so there is no orientation problem.

?Replacing substrate - will I not need to replace it anyway with fine sand to avoid the eventual octopus from hurting itself?
If it is sand, no. If it is sharp pieces of large crushed coral it might be a good idea. The octo does not need "sugar" sand (extremely fine sand like sugar, or at least the over refined stuff we get here). A sharp substrate could cause small cuts that in themselves are not serious but the likelyhood of infection is a big concern.

?What is the difference between distilled water and RO/DI water? We get distilled water out of our taps, it is exactly the same as what is in the bottles you can buy.
The process of purification. RO/DI water is tap (usually) water run through a series of particulate and carbon filters and then run through a very very fine membrane (the RO, reverse osmosis part). The final stage (DI, or deionizer) is a silicate sand that removes metals suspended in the water. Distilled water is water that is turned into steam and collected using a distilling process like making alcoholic beverages. The slight advantage to sealed distilled water is that the distilling process kills bacteria where the RO/DI process does not. Your tap water will not retain the bacteria free advantage and may contain chemicals to keep it bacteria free (chlorine or something similar). I would not know how to determine if you could use tap water since our water is cleaned but they add chemicals to keep it that way (mine contains a lot of particulates). Since an RO/DI unit is available, it would suggest you have chemical additives.


That's great, thank you! I think we covered everything there for now, no doubt I'll have more questions tomorrow or the day after :smile: I've added a colander to the list of things to grab from the grocery store tomorrow.

I've planned to drive to Oslo at 5 tomorrow (which I guess is about 8am in California) to get to the large aquarium shop and then onto the aquarium seller a few hours later. I looked after my neighbour's injured cat for a week just now while she was on holiday so she was happy to lend me the money for an RO/DI filter for a few weeks when I very politely told her my plans :P (lucky!) My ex-boyfriend said he can drill the holes for the wall bracket etc. if needed so that's covered.

Had a talk with the seller, he has never used copper in the aquarium but he did buy it used himself so I will take something to test the copper level when I go. He feeds the fish shrimp and doesn't do much with the corals at all, I think he said he adds calcium and one other substance occasionally. In any case, he said he would give the remaining food as well as all the test kits, a hydrometer and thermometer. The protein skimmer he has is rated for 400-600L he says (200L is about 50 gallons and 180L is a standard tank size here it seems), so I suppose I might get away with that with the octopus? I have budgeted to buy a protein skimmer for 600L in any case.

I think that covers everything on my mind at the moment :smile: So I have on my list for tomorrow, a number of buckets, salt, shrimp, small net, algae scraper, copper tester, gloves, colander, sand depending how coarse the existing substrate is, a siphon and a toothbrush lol, with the seller providing the tank, filter, lighting, protein skimmer, test kits, hydrometer, thermometer, and food for the corals. This is turning into rocket science for me now, I sure hope I remembered everything! :smile:

One last thing, on the RO/DI filters:

At the top of this page is listed three Aqua Medic filters, all produce 90-150L per day, all say they remove 95-98% of the bacteria. But the 2nd and 3rd ones are twice as expensive and the 1st and the descriptions of the 2nd and 3rd are the same although they look much different. What is the difference between these items?

Wish me luck :) I'll post pictures tomorrow or Thursday morning.


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I would not bother with a copper test kit. If there is copper from before the current owner, it will be too small to detect (but still could be lethal) so the test kits are pretty useless for this.

I can't translate (I have heard it said that people are tri-lingual, bi-lingual and American, I am the English speaking only later :oops:) the information in the RO units but the third one looks familiar enough to identify two particulate canisters and a reverse osmosis (RO) filter. What I don't see is a deionizer (it will be a sand filled container but may be opaque, mine is transparent). In the others I don't see the typical particulate canisters but the shape of either of the other two may be DI filters. Do you know if you have high mineral content in your water? The DI part of the filtration takes out the minerals and metals (copper being the most imporatant to remove). Ideally you will have one of more particulate filters, one or more carbon filters (for chemicals), a single reverse osmosis filter and a DI (deionizing) filter. The greater the number of carbon and particulate filters before the RO the better you can extend the life of the RO membrane (the most costly part of the system).

We may turn you into an aquariest yet :grin:

PS, I am also a Computer Programmer.


Ok, thanks for the explanation. I know that (and was told again on Monday by the saltwater guy I met) the water here is extremely clean; almost every town is by the ocean so there is not much pipework that the water has to travel through. It is more or less just desalinated and sent to our homes. What the mineral content is, I have absolutely no idea.

Reading the instruction manual to the first item on that page, it mentions reverse osmosis but not de-ionization. I will ask about Norwegian tap water quality when I go to the aquarium today and what is needed. I am quite sure the water here is much cleaner than what the average American home receives at the tap, but the aquarium will surely know what is needed to make it safe for a saltwater aquarium.

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