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wanted: tank cleaner

Jan 23, 2008
hi again all! i'm not sure if this is where i should post this question, or if it should be in tank set up, being that it is not a mechanical issue, i thought this would be best. i have a tank with 4 bobtail squids. i lost 3 in the past 36 hours due to bad water. i do alot of water changes (25% 5-7 times a week) with filtered water and have a pretty good filter/protien skimmer. so this morning i did a full water change and found that the problem is with my sand. it stunk, so i took the tank apart, scrubbed it with fresh water, and washed the sand. while i was sifting through the sand i found about 100 peices of shrimp. aparently the bobs aren't eating the heads and in some cases just killing the shrimp an burrying them. i use super fine powder like sand for the bobs to burrow in. what can i do about all these shrimp fragments? i would think that going in there every day and sifting through the sand would be very stressful to the bobs, and any filter that can pull shrimp parts out of the sand will also suck up the sand. i was thinking some sort of non-aggressive tankmate? something that would only eat the dead shrimp peices and not the live shrimp or my 2 baby pea sized bobs. something that would "dig" through the sand would be a plus, because the bobs seem to like to burry their uneaten peices. anyone have any ideas? your time and wisdom are much appreciated!
What's your tank history? I'm a worried that if you washed your sand and did too many water changes that your tank is likely to cycle again... do you have live rock? Did you have the tank cycled and stable before you put the bobs in originally?

I don't have time to look right now, but maybe there's information on the web or published in journals about keeping Euprymna scolopes in lab conditions, since they're frequently used as experimental animals (although often at places that are likely to have flow-through systems that use seawater directly), that would describe the best type of sand and ways to deal with habits of burying their garbage... I know they prefer to spend a lot of time buried, so it's not too shocking that they'd want to eat their shrimp under the sand and just leave the dishes there for someone else to deal with.

This might mention something about it: http://www.cephbase.utmb.edu/refdb/pdf/7724.pdf but I don't have time to read it now, and Woods Hole has flow-through systems, so they may not need to worry about cycling and other closed-system issues so much.
As monty mentioned, please describe how long the tank has been setup and what is in it that can function as biological filtration such as live rock or bio media like bio balls or bale.

In terms of scavengers that may eat the left overs, small serpent stars may help. If they get too large, I may switch them out to smaller ones for they have been known to eat small fish. I know some people dont like brittle worms, but I have many in my system. They have been there for a long time and are actually very large. Any left over pieces of food will soon have a few of these worms on them in no time. Im unsure about bobtails, but if they are like cuttlefish, you can also have hermit crabs which are also good scavengers.

That being said, large shrimp pieces that accumulate daily may be beyond processable by basic filtration systems and feeders and may actually require physical removal. Perhaps you can feed less and they will eat them more to completion. Cuttlefish seem to leave tails and heads of shrimps lying around as well.
If you are having to do that many water changes then something is wrong with you filtration, whether it be biological or mechanical. I cannot imagine that the tank is able to hold much of the nitrifying bacteria necessary to keep water quality in check, performing that many water changes.

Why so many?

i feed live shrimp which we go out and catch once a week. the shrimp water clouds almost as soon as i change it. (like i changed it last night at around 7:20 and this morning at 9:00 it's already cloudy.) since i don't see the point of giving clean water to my shrimp, i use the water from the bob's tank and give it to the shrimp, and then give the bobs the clean water. wedon't use any other type of filter because we do so many water changes. (overkill) i don't use live rock because we're afraid of hich-hikers. (with one of our previous tanks we ended up with something that kept hitting the tank at night, but never found out what it was. even after we took the tank apart. and my husband is afraid that we'll end up accidentally introducung a fire worm.) in regards to the tank history, we used real sand, washed in salt water, and filtered sea water from the DLNR. the tank sat for 1 week with the protien skimmer running. no chemicals were added. when we went tidepooling we had anticipated getting fish, but when we caught the bobs, we couldn't turn them down. (although we did catch a red lion fish, 2 flying gurnards and a baby flounder) they were doing fine for the first week and since i've cleaned the tank, the remaining bobs still look good. i think that if i solve this problem with the "leftovers" we'll be ok.
what if i place a clear container (with sand and shrimp) into the tank to feed them in, and remove the container to clean it. would they be able to figure out to go in to the container to eat? would it stress them out too much when i kick them out to clean it? would they stay in the container to eat? does the process sound too stressful? we're going to the petshop either today or tomorrow, i'll ask the guy for tips on scavengers.
Your aquarium setup is significantly different from the way many of us approach creating a saltwater environment. Most of us do not have the water access you use and have not tried to keep squid so suggestions are difficult and second guessing.

Without biological filtration, your water changes are probably not excessive or overkill and may not be enough to keep the water healthy since you must have a substrate for your wards (with fish you could keep a bare bottom tank that would not collect debris or contain live elements that will die off in a tank - rinsing the sand will not remove this concern, boiling it first might). I am not sure that a clean-up crew will resolve the substrate problems even without the natural biologics since they will digest the leftover shrimp but still eliminate it as waste (it will be processed some but it is still waste product that will build up toxins). A large cannister filter should help IF you stir the substrate regularly (so that the waste and toxins are available to the filtration unit AND your change out the filter regularly). Some aquarists supplement the biological process with hang-on filters and bio-wheels (I am not a fan of this type of filtration but others have had better experiences). An advantage to the overflow type filter is that it also promotes gas exchange and helps keep a higher oxygen content to your water (also a reason I suggest that you cannot over change the amount of water for this particular setup).

As an asside, the critter you heard banging on your tank at night was likely to have been a mantis shrimp, a critter that is considered highly undesireable in a reef tank but often kept as a pet in a species only tank.
HOw long was the tank up and running before you added the sand etc (I may have missed this sorry) but as I read your message you had the tank running for 1 week to cycle it needds a minimum of 3 months! Cephs need super stable water chemistry as they produce way more waste than a similar sized fish! If I missed the info sorry......but tis better to be safe!!


Jean;109835 said:
HOw long was the tank up and running before you added the sand etc (I may have missed this sorry) but as I read your message you had the tank running for 1 week to cycle it needds a minimum of 3 months! Cephs need super stable water chemistry as they produce way more waste than a similar sized fish! If I missed the info sorry......but tis better to be safe!!



Actually, Jean (and other lucky people with pipes to the ocean!), I'd love to hear how things are different (and similar) in your flow-through open seawater systems from the closed, recirculating systems. Presumably, the cycling is rather different, because there's not a buildup of waste, as it's flushed, but I assume various bacteria and other "live filtration" organisms to colonize, and go through blooms and die-offs. You seem to imply that even if LittleMarley does very frequent water changes that there will be a "traditional" 3-month cycle (and I wonder if the frequent water changes are likely to slow the cycling, reduce the "swings" of cycling, induce mini-cycles, or what?)

Maybe all the serious reefers already know this stuff, but I have the impression that most of the stuff I've seen on the web is from closed-system tank-keepers, so it would certainly be interesting for me... maybe to complement the excellent descriptions of cycling closed systems that are around. I remember someone (I think DHyslop) put together a great description of cycling closed systems with graphs, but I can't find it right now... I'd love to see a comparison of what the differences are with flow-through systems, and how frequent water changes might impact this...
Hey Monty,

I couldn't see in the posting if this was a new tank (ie not cycled at all bar the one week) or if it was an older established tank with a new filter, that would be a different kettle of fish (:grin:) A new tank with such frequent changes will of course never cycle completely and won't be stable enough for cephs. Even in an established tank I subscribe to the "less is more" school of thought unless testing shows otherwise!


We "season" the tanks usually for a minimum of a fortnight, and never wash the sand beds as they come from just outside the door, once a week (ish) we give the sand a wee bit of a stir and siphon off any crud. We keep polychaete worms (maldaniids etc) and some burrowing cucumbers (Paracaudina chilensis) & brittle stars (Amphiura sp) & chitons (Acanthochiton zelandicus) in the sand beds. Any closed tanks (we have a couple) are cycled for 3 months. The problem with traditional water changes is that they inevitably stir things up if done too often and knock off the bacteria (then you have decompsing bacteria in the mix too!) our open system has constantly moving water and although the bacteria does die off etc the waste from that is washed away (we don't have any bioball filters etc, we have sand filters and thats it!!!!!) . In our closed tanks we do a 50% water change once a week in summer and once a fortnight to three weeks in winter (or less...depending on bioload etc).

We can shut down the pumps and work the system as a recirc...officially we have enough reserve water to last 3 days, in reality it would probably last 1 day, then we'd have to release a lot of our stock (this would only be done in an emergency, say an oil spill in the harbour) We run through some 38,000 L every day.

We don't very often do a full "cycle" as the tanks are very rarely left to dry out (the only one I can think of was the octopus tank after an autophagy episode) Many of our tanks have been running for some 77 years!


It doesn't sound like this is really a flow through system, but a system that gets lots of water changes. If there is lots of rotting matter (shrimp parts), then just doing water changes many times a week is prolly not sufficient to keep up with decomposition.

Live rock is good for 'filtration' and I wouldn't worry about adding fire worms - the worry is overblown IMO.

Just about any sand bed will stink when you disturb it, so I am not convinced that there was anything bad going on in the sand. Having scrubbed the sand, it is no longer going to function as a 'filter' for quite some time.

The fast fouling of the shrimp water is a good example of how quickly water can foul. To make the water changes work as a primary means of exporting ickies, I would be doing at least 50% daily, and would be more comfortable with 90% daily being careful to not stir up the sand bed.

Also, the water you keep the live food in effects the quality of that food, so I would be keeping the shrimp water clean.

How long have you had the bob's? How much have you been feeding them? What size skimmer are you running?

In my ceph system I have a ton of bristle worms that do a great job of eating uneaten shrimp. So much so that I don't worry about it at all.
hi, sorry i took so long, i'm new here and didn't realize that there was more than 1 page.:oops: i've had the bobs for about 2 and a half weeks now and the survivors look ok. i am worried about the clean up more than the water quality, since they live pretty close to shore in a tidal area and in pretty nasty conditions. (at least that's where i found them) cleaning the sand is my main concern. we're still looking for scavengers. for now i go in and clean up by hand, which really stresses them out. what should i do when they ink. should i clean it, or let the filter take care of it?
Some people have made nets to clean ink... one suggested method is to stretch panty hose or over some sort of loop. It's often possible to let the skimmer take care of it (which is good, in case they ink when you're not around to notice) but cleaning it is helpful, too. I think the panty hose thing is described in one of the octopus care articles....

I'm not sure what the best strategy is for you... it sounds like you didn't set up biological filtration and get a full cycle, so some combination of water changes and brute-force filtration is all you're using to keep the water clean... this certainly isn't what we recommend, since cephs are known for producing a lot of waste... do you have an undergravel or canister filter as well as the skimmer? In addition to the water changes, you may want to change filter media often.

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