Bristleworm question

[StevesLEDs]

Right now, I have nothing that will survive to turbulate my 4" deep sandbed in my main tank. (nassarius snails just die after about 2 days) Should I throw in some bristleworms? Or would that be considered bad practice? I have tried sand sifting stars, but I think they ate all of the other critters in my sand, so that sand is pretty stagnant and now no critters are left. Plus, the sand sifting stars were messing with my tanks biological filter because I'm guessing the critters that were in there prior to the starfish churned up the sand enough for a good filtering effect.

Any thoughts from the experts? Should I go with bristle worms or put more sand sifting stars back in there?

 

[mukymuk]

IME, you really can't have any predators in (above) your sanded if you want it to function as a NO3 filter over the long run. I think your stars would simply eat the worms in pretty short order.

4" puts you at the edge of DSB territory, so it's a tough call which way you should go. But if you want it to behave as a filter, then you probably have to get rid of the predators.

4" is a lot of sand to maintain sans-DSB though (that is, with large sand-sifters and occasional vacuuming). So you might have cornered yourself into running DSB style or bust.

 

[StevesLEDs]

Well, I'm running a refugium and sump with live rock for a NO3 filter. I don't do water changes because I have a denitrifier. (haven't done one in years with all systems nominal). I'm not really interested in doing the DSB route....does that make it ok to put in sand sifting stars our should I just grow some more worms?

 

[mukymuk]

There are other reasons to do water changes, but that's a different issue.

If you don't care about the sandbed for purposes of filtration, then yes, just put whatever you like in there with the understanding that you will need to periodically clean it. Some say that even well stocked DSB's eventually need overhauling as well.

All that aside, I think you'll have trouble establishing anything, including worms, in your sand if you have predators like starfish in there. Might be worth a shot though.

 

[Wes]

outside the other aspects involved here, dont have sand sifting starfish. dont. they cant be sustained in our tanks and especially not if you want your sand bed to be alive and working for you not against you.

small critters in your sand will move it and agitate it enough. flow pushing on it from the top will help move things. i would recommend buying a detritavore package from online to revitalize your populations.

see this site - http://www.inlandaquatics.com/prod/prod_detrit.html
and this one - http://www.ipsf.com/

 

[DaveJ]

My experience after nearly 8 years running a DSB... you need to establish it correctly from the start and maintain it. The purpose of the DSB is denitrificatiion. In order to achieve that, you need something stirring the sand, this includes sandbed clames, worms, bacteria, nassarius, conches, cucumbers etc. Anything that will eat from the sand, such as starfish, gobies etc should be avoided unless the bed is large enough to handle the predation. I had a sand sifting goby for years in my 140, but the sandbed was 2'x4'x7" deep. If you have LR etc on top of the sand, that is not a functioning DSB under there....

Two things you mentioned that cause me concern, first is that you can't keep nassarius alive. You may be getting bad snails, but if you get quality snails, acclimate them properly and have enough meaty food for them, you should be able to keep them for a few years. The other thing that concerns me is the denitrator... its quite possible the denitrator is pulling everything out and the DSB is just processing what little is left. A denitrator is a highly efficient nutrient reduction tool and if your DSB is of proper size and health, shouldn't be needed at all. In DSB system, they should be used to provide additional function to pick up the slack if your bioload is too high for the skimmer and DSB. The lack of water changes is also a concern.... a denitrifier is NOT an excuse for not doing water changes. Water changes are still needed to replenish elements and minerals.

Worms are in the tank, so adding more won't do anything.. you need to focus on getting sandbed critters, pods, some sandbed clams, conchs or cukes otherwise your bed will clump at which point it becomes a nitrate and PO4 sink. If for whatever reason, you can't keep the bed going, I would remove all but an inch of the sand for that reason.

Incidentally... when I removed my old sandbed that had been up for nearly 2.5 years during the switch to the 300G, we scooped out all the sand and it was almost as clean as the day it was put in. No smell or anything despite the normal discoloration on the sides, the blues, greens, blacks etc you see on the sides. There was a bunch of life in the bed as well.