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How bad is city tap water?

Pennyworth

Wonderpus
Registered
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Dec 13, 2013
Messages
192
Location
New York City
So I live in NYC, and paid for the best aquarium shop in the entire city to build and setup a custom tank for housing an octopus.

I had done some reading saying that tap water was not OK to use, but he filled up my tank with tap water. The right amounts of salt, minerals and buffer and whatever else is necessary, but still...it was tap water.

As the water evaporates and I refill it...with tap water....I am wondering how concerned I should be about this.

Just how bad is city tap water on average?

Will the ceph be fine, die straight away or something in between?
 
Tap water is very bad. It has ALL KINDS of crap in it that you dont want, including copper. If you have a TDS meter you could test that most tap water (here in Houston Texas) runs at about 218 ppm (parts per million) of stuff. Thats 218 ppm of copper fecal matter, mouse droppings, dirt, medicines (antibiotics, pain meds etc) heavy metals etc etc etc.

If you were to measure some bottles of drinking water (ie nestles or ozarka... basically anything thats actually been filtered, NOT dasani as this is not filtered and is straight tap water) you would see that they are roughly 19 ppm. This is what basic RO water will give you. RODI water will give you 00 ppm. But things like calcium and other bacteria can still get through. The only PURE water that I know of is distilled water which is water thats been boiled and then the evaporated water is collected. All of the calcium ect is left behind so its pure.

The RODI water is good for octopuses and reefs. Please change out this water with either distilled OR rodi as anything less will cause you problems.
 
Water runs a huge gamut of variations in our country and NYC is noted for some of the best (healthiest) drinking water (a link on your water you may want to read). However, drinking water safety and aquarium safety, especially for inverts, are not the same. As an absolute minimum, even exceptional tap water needs to be dechlorinated and deionized (metals removed, the DI part of RODI water). Chlorine will eventually evaporate if left out but will be present in any tap water from a public supply and should NEVER be used without being left open overnight to remove the Chlorine. Since you are setting up a new tank and nothing will be placed in it for a long while, your set up people did not error with the Chlorine concerns but you cannot use water directly from tap for top offs after you have animals in the aquarium (this would be true of salt or freshwater aquariums). Fortunately NYC does not use Chloramine, a harder chemical to remove that can cause serious problems, particularly with the PH requirements for a marine tank. Here is a nice article that includes info specifically about NYC water and aquariums as well a the problems with Chloramine - something Sabrina has to deal with in TX). Note that it does not discuss the DI (metal removal) needs for inverts.

Deionization, however, is an oversight by your set up crew. For a fish only aquarium, the metals found in tap water are usually tolerated and fish are frequently treated with copper to kill parasites. Unfortunately, invertebrates (as well as most scaleless fish like dragonette) cannot tolerate copper, even in small amounts.

Most bottled drinking water (including Dasani) have been through the RO or RODI process (ie filtered) but minerals (including metals) are added back for taste and make it unsuitable for aquarium use.

Some stores (often saltwater aquarium stores, Walmart did at one time but have discontinued in our area, you might also check your grocery store) will have RODI water that you can purchase very inexpensively if you bring your own container but the maintenance of the RO and DI components is always suspect from a DIY filling station so if you purchase it, get at TDS meter to at least validate the reverse osmosis (RO) component is removing particulates (Total Dissolved Solids should = 0, my tap is 34ish AFTER whole house particulate filtering). Any RODI water should show a PH of 7 (neutral) that should increase to your tank's 8.4 when added.

Home units are great to have if you can dedicate a water supply, not usually viable in an apartment but non-destructive to a rental home with a spare sink. There are some smaller home units available for apartment use but are usually thought to be inconvenient and messy so most renters opt to buy their water.

At least one of our staff uses Deionized tap water successfully (CA). My water (GA) is totally unsuitable and must go through RODI filtration for both acid and particulates.
 
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I was unaware that Dasani was filtered. I did make an assumption about it not being filtered as I tested the Dasani with a TDS meter and its was some where in the range of 200 ppm. I took that to mean it wasnt filtered. Sorry for miss information.
 
LOL, since Neal's diagnosis with diabetes, I read ALL labels and do a lot of looking things up! However, with Dasani, I looked it up before because I wondered why it tasted so much better than my tap or other bottled waters.
 
Thanks all,

This is quiet disconcerting.

I found this chart (page 10) which shows the amount of metals in the NYC water, but I wasn't too sure how to read it.

What I would like to know....is what are my options now? Can I still use the water in the tank which has been cycling if I run it through a DI process, without removing all the things that will be needed?

I would hate to have to start from scratch again.

I can buy RO water for topoffs, but need to deal with the water I am cycling first.
 
I wish I had a good answer. The best I can offer was to look up traces of copper found in seawater (.00038 mg/l if I did the conversion from 380 ng/l correctly) vs the .025 - .003 mg/l listed in your chart for your water. As you can see, this is not a happy comparison. Unfortunately, we don't have a quantitative amount that can be tolerated or an estimation of accumulation that is lethal over time. It is strongly believed (again, anecdotal evidence only) that amounts lower than we can test at home are lethal. I have never used water that did not go through a DI process so my experience is not helpful and I am not sure how to recommend how to proceed.
 
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So I've spoken to the guy who set it up...

I'm going to get a copper test kit, and I think if I top it up with RO water from now on it should be ok.

He also suggested using a poly pad to take stuff out of the existing water. Does anyone have an idea how reliable that is?
 
Unfortunately, the copper test kits available to hobbyists do not test for small enough quantities and would be a waste of time and money.

I have used polypads for very small tanks as filtration but not on a larger tank and not on an octopus tank. I did experiment with a 1.5 gallon and a penny to see if the polypad would detect (turns blue) and remove the copper. It did but, again, it will not remove enough to make a copper exposed aquarium safe for sensitive invertebrates.

Topping off (adding freshwater as water evaporates) will do nothing for tank pollution or removing minerals. Water replacement (siphoning off saltwater and replacing it with saltwater when you clean the tank each week) will help dilute pollution and undesirable contaminants. The amount and safety of the water in this case is not easily quantifiable and I can't think of a good test scenario.
 
So polypads are not sufficient. Is copper the only main concern with the minerals from tap water?

I bought a API copper test kit before I read that it probably wouldn't be useful. This older post mentions the seachem testkit might be somewhat useful.

I am hoping for a way to test the copper and hoping that it somehow is perhaps low enough. That being unlikely, is my only resort then to empty the tank and clean it and start again?
 
I wish I could give you a confident answer but I can't. The lethal quantity of copper is unknown but anecdotally, very, very small. Your research (great find) shows that your water, even at the lowest concentrations, far exceeds the small quantity found in seawater (the only amount we can assume to be safe).

If I was in your situation and point of hobby, I would likely go for heavy water changes (not top-offs), an over long cycle (never a negative) and hope for the best. However, today, I would drain the tank, soak everything (including the sand or just replace it) in new circulating, frequently exchanged RO/DI saltwater for a week and restart the tank. This would not kill your live rock and will only delay your cycling but is expensive and work intensive.

An alternative that may not be appealing would be to keep the tank as a fish only aquarium. The small amount of copper you currently have in your system will not be a problem for scaled fish. Scaled fish are treated with copper to eliminate parasites (and one of many reasons they should not be place in an aquarium with an octopus). This is almost always done at least once somewhere along the wholesale/retail supply chain. Fish are easier to keep than cephalopods, live many years longer and are a better way to begin learning to keep a saltwater tank. Everything that you have learned and done still applies to fish (and you should NOT treat fish with any medication in a display tank so you should not add copper to the tank at any time).
 
So basically the people who set it up are making their own octo tank for the store are convinced it will be ok because they have cuttlefish and such. They were not really listening to me when I told them how the octopus is far more sensitive...

Just waiting to see how it goes and will give these people some leeway, but will have to take action if it turns out they were wrong...which they may well be.

I'm going to buy an 3 stage RO water filter system....are there any suggestions for a specific system that people prefer on here, or are they all more or less the same?
 
Octopuses and cuttlefishes should be pretty much equivalent in copper sensitivity (this is just a guess, squid, also cephalopods have been known to handle less pristine water) where other comparisons ("and such") would not be valid (as mentioned most fish and some inverts can survive in other conditions). That being said, one of the problems the hobby has with LFS, "we do it all the time" or "we have no problem with ..." comments is that they, by design do not hold their animals for long periods of time, they don't check on the survival rate of the animals they sell and they cannot be experts on the diversity available. This does not make them wrong but it does add a warning label to their advice. It is a concern that they are not already using RO/DI water and you might "innocently" ask someone who does not know your concern if they use straight tap water in the store.

I have never seen a convincing write-up on the pros and cons or any RO/DI system. The strongest comment come from the amount of waste water (you will need to place the unit near a drain to flush the water that does not pass through the filter - roughly 4 gallons of waste for each gallon of filtered. This is a function of the pressure and the RO filter) and the amount of time it takes to produce the water you want to use. Since you will be setting up a temporary system, you will likely want to put the whole thing (unit, receiving bucket and drain hose) in a tub and let it run overnight. By using a tub, if (when) the bucket overflows, you will not have a mess (voice of experience). A sink works too but a tub give you more options for a larger bucket. I recommend getting two 6 gallon pourable water containers (these are the ones I use but in a slightly different way) and initially filling both with the RO/DI water and a third 6 gallon bucket/container to mix your saltwater for water exchanges (about 10% a week). The mixing bucket should be pourable as well but needs a larger opening for adding your salt. If you mix only what you are going to need, then it can be open topped. A small circulating pump and 24 hour mix time is recommended. In a more permanent setup aquarists will keep all the fresh water in one large stationary bucket and draw the water off as needed for top-offs and exchanges but you will likely need to move the unit and freshwater so the smaller containers are more practical (6 gallons x 8 pounds = 48 pounds per container).
 
The as such was referring to nudibranches...which is in the same order as Octopuses and Cuttlefish I guess. I will wait and see what the store says for now.

I'm buying an RO/DI system to top it off and for the future. Dwhatley just to confirm, are you saying you think I should put the water in my tank at the moment through the RO/DI filter?

I'm not going to drain the tank at the moment but the store offered to drain and replace with premade water if it comes to that. But I want to be topping it off with RO/water at the least.

How often would you need to top off a 50 gallon? I've topped it off twice so far but need to get better at it knowing when it needs to be done so.

Thank you for your detailed replies.
 
Yes, use RO/DI water from here out so you won't be adding undesirables, regardless of which way you go. Remember, you won't be removing or even diluting anything when topping off. Only water changes will dilute.

The need to top off with fresh water varies with tank set up (open/closed top, open/closed sump, surface areas of both) and with the room conditions (dry, humid, heat). There is no "standard" so you will have to gauge from observation. The general thought is, the more consistent you keep your water (evaporation will make the water more salty) the better. Many people (sadly not me, too many tanks in too many locations) create auto-top off systems that range from simple (bottle arrangement with float shutoff) to sophisticated (tubing running from their RO/DI unit). Automatic setups drip small amounts of fresh water into the tank on a continuous basis and are great if you can set one up (but kind of ugly unless you go with the more sophisticated setups. They do run the risk of overflow if the float get stuck.

Nudibranch (gastropod) and cephalopods are both in the Mollusca genus but on different branches of the tree of life. All inverts are sensitive to copper but the degree varies as well as the diet. I have not kept or studied nudis but I know snails are nowhere near as sensitive to copper so they would not use them as an observation metric to determine tolerance. As an aside, I have thought about trying to keep these beautiful exotics but their dietary requirements are very species specific and above my challenge level.
 
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