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110g tank in the works =]

Omega

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I've got a 110 gallon tank setup with a sump filter-protein skimmer to be added soon-. Currently I've got about 50lbs of live rock, and about two inches of sand. I've been told one pound of rock per gallon but I read on one of these forums that for an octopus you should have two lbs anyone confirm this? Also I've read that some octopi will rearrange live rock and that it can break glass, Has anyone have a problem with this or do you simply anchor it somehow? I'm trying to figure out the set up a little better before I keep adding rock in. The tank is just about a month old, has some snails and hermit crabs inhabiting it right now..though I'm aware they'll be snacks when I finally decide its ready for an octopus. Thank you all for your help =]
 
I have not seen any posts about glass breakage, however, SueNami caused tsunami type rearrangement on one side of his tank when we provided a feeding stick (zip tie) that he could not pull down into his den. He was very insistent that he wanted the tie and gripped the LR to try to pull the tie through the lid. The result was an hour reconstruction on the left side of the tank (this tank is divided by two 8" tubes) and then a complete reset up after he died.

A lot will depend upon the size of your rock and how you pile it but glass breakage is more a thought than a reality. We used Gorilla Glue to secure the rock in our first octo tank but subsequent tanks have not had the rocks glued down and only the mentioned incident has caused major excitement. They do rearrange the rock to some extent (more if you end up with a female who will typically do a lot of rearranging just before she broods). Ours have chosen a back wall cubby in most cases and as they have grown, they have pushed the rock outward to accomodate their larger bodies. Anything that moves during regular cleaning should be reconfigured.

Remember that they will climb all over (and under) the rock when they hunt so a sturdy "pile of rocks" setup is better than some of the more esthetic designs unless you artificially stabalize. Epoxy will not hold rocks together over a long period. So far the Gorilla Glue has held in both the first tank and our 4' tall anemone/clown tank where I have the rock attached to a piece of egg crate to create a 3.5' x 1' wall (I wish I had found the Gorilla Glue at the beginning of that project, some is/was epoxied). Drilling a hole and using acrylic rods to join the pieces has been very successful for some of our other members.
 
I have alway followd the 1 lb per gallon even in my ceph tank. too much rock and your going to reduce the amount of room the creatures have to move around.

I just piled mine in the tank, and made sure I left enough caves and cracks for water flow and creature traffic. So far I have had no problems, She moved a few of the smaller rocks around but for the most part she just travels around the tank molesting the rocks, and hunting. I was playing tug-o-war once and she grabbed a medium rock off the top of the pie and it moved but it scared her and she put it right back.

I used the drill and rod method of holding decorative rocks in a old freshwater aquarium I had and it worked fine, it was a pain drilling all the stones, but live rock would be easier drill. I also used copper rods from the hobby store, which I guess is a no no in a ceph tank.
 
I was thinking one pound as well to leave room for movement. I seem to be having a bit of an algae bloom now just over one month into the tank. The tank was cycled with "stability" for a week, then snails and hermit crabs were added, then a yellow tang i named molly(she kind of came with the snails and crabs). They've been in the tank at least two weeks, and have been fine the entire time. Molly is a bit odd for a fish(I've had fresh water aquariums my whole life) hies almost all the time unless its to eat. She refuses anything but red seaweed which I've read is common for her species. The algae bloom is coinciding with the very first detectable ammonia/nitrite,nitrate in the tank. Very low levels, but the first time the test picked up on them. I'm going to transfer molly to a smaller tank pre-octo so there isn't a problem. The live rock is doing well, all of it has algae and a good amount is actually Coraline already. Is there something I might be doing wrong that's causing ammonia to raise and algae to bloom rapidly? or is this a typical algae bloom for a first year tank I've read you usually have several the first year?
 
update...my previous post was based on amonia levels last night, i tested again this morning and found the test to come out quite a bit worse. i did a 10 gallon water change and added tra conditioner to neutralize the ammonia. I've been inspecting the tank looking for perhaps a dead crab or something that might have aided in the ammonia spike. I found pieces of one crab that has obviously been eaten. I am unsure however what In my tank could have eaten a hermit crab, unless there is some kind of stowaway in the last live rock I added. I found a bristle worm, which i was unaware of and it looks like there might be some other kind of tiny bug/worm I am unfamiliar with inside the rock...it would appear the LFS in fact did not prep their live rocks as they suggested =\
 
I have heard of some very surprising stowaways including Octopus! I have a piece in one of my tanks that at night comes alive. as soon as both the tank lights and the room lights are out hundreds of tiny tenticles come out of the rock and feel aroumd the tank. I added a "moonlight" to the tank but the tenticles did not come out with it on.
:sink:
 
Do you hear any clicking coming from the tank? I could be anytime but one of our hitchhiker Mantis shrimp would pound on stuff at night. Unfortunately, during my attempt to remove it, it aluded me but not the octo in the tank. Look at your rocks and see if you see spongey grey stuff. This will be sponge (often not initially visible and inside hole)s. If it dies the ammonia spike would be typical and you need to remove the rock, clean out the sponge and then put it back. Smelling your rock will often help spot this kind of problem. Not all sponges die but many do and they are generally removed in cured rock.
 
I allowed the room to get pitch black for about an hour then flipped on a dull flashlight and looked around the rock, I spotted a very thin 6-7 inch bristle worm scurrying back into the rock. I've read they can be very damaging to tanks and once large to smaller crabs and my hermits are blue legs so I decided to take out the rock and crack it into a few smaller pieces(it was a very good sized chunk) I found two stowaway emerald crabs, an odd variety of worms I'm not at all familiar with(looked very much like a white earthworm) and TONS of little bristle worms, and the larger one I spotted earlier. The rock had already been in the tank over a week but it does appear to have not been cured at all as advertised. I'm going to re-cure it and use it for my feeder tank =]. sadly this still doesn't answer whats been eating my hermit crabs.


Tested ammonia again, its now .4ppm which is still high but much lower than the spike i tested this morning I also added some water conditioner to neutralize the ammonia. Molly is out and about eating so I'm not sure she is to bothered by it. I'm going to set up a cycling tank for live rock after christmas. Can anyone tell me if using an old freshwater could be dangerous? I cant say for sure whether or not it ever came in contact with copper..if I clean it up with it be safe to cycle live rock in? or could the live rock absorb some copper out of the silicone?
 
Freshwater will kill the LR (aging does not matter) and the internal die off is likely to produce lots of ammonia without creating a natural cycle. It will kill the brissles but, as you mentioned, they are not killing things in your tank and you will have to decide if it is worth killing the LR to remove them. You can try a 15 minute saltwater dip with a very different PH and salinity (either up or down). It would be less damaging to the LR bacteria and may force many of the brissles out, Shake the rock vigorously then a scrub and into a cycle bucket (just a plain bucket with water movement would be better than risking copper exposure). If you are not finding sponge, and have somewhere to put the fish, I would just let it cycle out naturally. I would suggest NOT using the ammonia remover and doing water changes instead. In general, chemical additives will slow or stop the natural ammonia->nitrite->nitrate cycle that you are trying to achieve.
 
ammonia levels stopped rising, nitrite and nitrate going up so I guess the bio filter is kicking in some at least, still finding crab legs. completely out of ideas as to what could be killing them. Ever heard of blue leg hermits eating each other? or perhaps one of my two stow away emerald crabs?
 
Since removing the new rock seems to have stopped the ammonia climb, you likely have found the culprit. Do look closely for sponge and do scrub it to remove dead material.

Emerald crabs don't eat hermits and are usually beneficial to a tank for algae control. Supposedly they are vegetarian but I have noticed that you can have too many in a tank at one time and that the population will reduce to what the tank will support. I have never been sure if they eat each other when they shed and are in the softshelled state of if the food source is actually the reason but I have seen the population control over and over in my tanks.

There is another possibility if all you are seeing are legs. All crabs shed their exoskeletons as they grow and the shed looks like a dead animal. If you are not seeing a reduced number of hermits (hard to determine), you may simply be seeing healthy growth and a lot of shedding. They will fight for shells but I am not sure if they actually damage each other often. My guess is they rarely kill each other since I don't seem to have a changing population.
 
the ammonia was a little higher today, but the nitrite was the same as yesterday and nitrate was up..so the bio filter is for sure working. The fish, crabs, and snails all seem fine and unphased by the imbalance so far. I moved the overflow and pump that brings the water back from the sump around a little and the water seems alot clearer and clean. I originally had it set up how my lfs told me but I never thought it was an intelligent way to do it. They also happen to be the store that sold me that live rock =\. I did find some type of thick brown goop in the rock..possibly dead sponge? overall I think the tank is catching up and correcting so I think my crisis is winding down. thanks to everyone who has been giving advice =] I'd be lost without this site.
 
The brown goop could well be your ammonia culprit regardless of what is was when alive. Stick some in a cup and test the ammonia in a day or so (or just smell it- there are few - Xenia being one of the exceptions - things that stink when they are alive) if you want to experiment. I am glad to hear it is settling down but this is a good demonstration of why we say to wait a minimum of 3 months (an octo would not likely have survived) and why so many people go through "new tank syndrome". Most LFS's would have said to start adding major livestock since your initial parameters seemed settled. If you decide to add more liverock I suggest setting up a bucket with water movement and letting it cure for at least 3 weeks before adding it to your tank. I used to keep a large bucket in the garage but I no longer expect to be adding tanks so I use my two 10 gallon feeder tanks for the few "extra" pieces I keep about.
 
Finishing touches- I'll be adding 90lbs of live rock into the tank at the end of this week, provided the curing tank still shows good chem levels. I'm going to try and build in some caves and tubes through the liverock out of pvc. Whats a good glue/tie maybe to hold things together? and do I need to do anything special with the pvc before adding it? I know allot of people mention having it yet dont mention how they cleaned it to prepare it for an octo tank. Are most PVC pipes safe? Also thought about finding a hard plastic sphere to use as a cave and just surround it with live rock...but again how can you be sure the plastic will be safe? I know there have been plastic toys and a lego block used in the past in tanks.
 
General rule of thumb with plastics is that if it is food/infant safe it should be aquarium safe (PVC pipe us used for potable water so that counts). Other plastics have been used but with some of the materials we are finding in them I tend to stick with clear acrylic. Anything with paint is a bad idea.

I have used Gorilla glue in several tanks (including an octopus aquarium) with no harm and swear by the stuff.

IMO a ball would not make a good den. Most of my octos have taken dens with multiple entrances and exits (the mercs are an exception though). The hummelincki seem to prefer a gentle water flow through their dens and pick places near the Koraleas (especiall to brood). Something more like a whiffle ball with very larg holes might work but then the octo could not easily block intruders.
 

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