Not really sure where to put this, so mods please remove the thread if I'm in the wrong forum.

Aim: to recreate a free living soft bottom coral community similar to that found off Lizard Island in the GBR.

Feature coral: 3 x Heteropsammia cochlea ie 'walking dendro' . I was drawn to these because of the symbiotic worm that carries the coral around as it forages for food.

Other corals will be selected according to whats found in the relevant biotope in the wild eg Catalaphyllia, Diaseris, Trachaphyllia, etc...

The above tank dimensions will probably be 24" x 18" x 12". Very low flow compared to most reef tanks & low light.

Here are my questions:

I was going to set this up as I'd usually set up a reef tank: weir, sump & return pump. I could house a skimmer in the sump. But I was told this is unnecessary in such a small tank, and that I could easily use an undrilled tank and just rely on 30% weekly water changes. Now although this tank will be fishless, I will be spot feeding the stoney corals. My concern is a build up of nitrates / phosphates. Will the water changes take care of this or am I better off with a sump etc... so that I can house a skimmer?

Thanks for your time!
angie

My personal thought would be to go with a sump.. I think it would benefit with a sump and skimmer. I would still to semi large water changes as I think it will still be necessary unless you feed little and vaccum what is missed.

Curious what your thoughts are for CUC in this type of setup.

Thanks for your input Degener!

I'm completely new to small tanks but not to reefs or maintaining water quality etc...

My thinking is if I use a good quality over rated skimmer I don't really have to worry about how much I feed (within reason). Its just that some of the inhabitants will require bits of whole prawn etc 2 X a week. Or is there a reason this thinking is wrong because of the small tank size & quick nutrient build up etc...?

The only thing I can actually see working against me is low flow. Usually high flow means crap is suspended and makes its way over the weir and down to your skimmer. Here I'm a bit concerned the debris might just sink to the bottom. So a very 'live' sandbed is critical to success, as well as providing food for the worm. Guess I could go for a HOB skimmer, but IME these are pretty inefficient.

As for CUC I'll be innoculating the DSB with mud from the bottom of LR tanks. I have done this in my DT and its teeming with life. There'll be enough omnivores from there to take care of any solid leftovers. I'll add a couple of varieties of herbivores (especially snails) but definitely no fish, crabs or shrimp. I'll be trying to maintain biodiversity and its really hard to do once you keep ornamental shrimp / most fish etc... There'll be very minimal LR as its not part of the habitat.

Are you going to run a real DSB or just alot of sand. The reason i ask is if your just going to run alot of sand you will want it turned alot especially in a low flow tank .. Nassarius Vibex would do well for that.

If your going to run a true DSP and allow the de- nitrifying bacteria to build then you dont want to disrupt the sand bed except to keep the top 1" clean approx in which case a sea cucumber or a sifting variety would be good I think umm tiger cucumbers do this.. I forget and there may be other things in your biotope area that do this.. just a thought

As far as skimming goes 2x feedings a week with an active sand bed and something to clean the surface afterwards i think you will be fine even with low flow. My concern was having something to clean up the left overs but sounds like you thought of that.

Yeah, it'll be a true DSB.

I know some species of ceriths turn the surface layer over and thats all I'd need. TBH I'll be avoiding Nassarius sp., as the ones we get locally appear to clean up other living critters in the sandbed. I figure there'll be enough other carnivorous worms etc and I won't need more.

If I can find a small cucumber that grows a maximum of say 3" that'd be good too.

to our forum!

This sounds like a great idea!

Tagging along!

pebbles glad to see you made it. It's me ckreef from over on RTAW

Another thing you can do to help clean up after a feeding is have a sponge filter down in the sump. An hour or so after the feeding use a turkey baster to get the "leftovers" back suspended in the water column so hopefully the filter sponge can remove them. An hour after that yank the filter sponge out and rinse.

You would want to make the filter sponge really easy to access so as not to be a PITA every time you feed.

In my little Pico Lamp I do a light feeding once a day for 2 days in a row and then on the 3rd day clean out filter sponge and do a 25% water change. It seems to be working so far but the tank is very new so hard to tell how this feeding/maintenance regime will hold up over an extended period of time.

Thanks for the welcome guys!






I'll give that idea some thought.
ATM I'm wondering... wouldn't a good in sump skimmer do a better job?

Yes it probably would but ... if you plan on heavy feeding having a mechanical way to remove the leftover food shortly after the feeding would help get it out the cycle before it starts to break down. That leaves the skimmer to work on stuff that is already breaking down.

mmmhm those Heteropsammia cochlea always looked interesting. there are always quite a few on live aquaria's divers den. good luck!