I love SPS but haven't been able to keep them!! I don't know if its lack a stability or the hodge podge setup I have right now. When I get the new system up and running and things setup the way I want them then I will be trying sps again.
Eric
I'm not sure the depth of the sand bed (either deep or shallow) will make it easier or harder to maintain SPS. IME low nutrient levels and a stable alk are the key to keeping SPS. When I say stable, I mean very stable. Once you hit a low nutrient level you'll want to maintain your alk between 6.5-8.0 dkh as many hard core SPS keepers have shown quite often that alk levels beyond those parameters (in a true low nutrient system) will likely result in SPS necrosis (and/or continual stress which will eventually lead to tissue necrosis).
I know many people have quite a liking for DSB's (DSB as defined as being > 4 inches), but for those of you whom are suggesting to use them, how long have you acutally had one set up without disturbing it or routinely cleaning it?? I've read several threads of tank crashes being attributed to a DSB which has been up for more than 6-8 years. A remote DSB is a great thing IMO as you can throw it out and start over if you find it leaching excess nutrients or toxins (hydrogen sulfide) into the water column.
If you have a DSB in your display I think you can prevent problems as long as you provide adequate aeration (siphoning, sifting inverts, sifting fish, etc...); however, that defeats the purpose your trying to achieve with having a true deep sand bed which is an anaerobic space for anaerobic bacteria to remove nitrates. IMO there are far easier ways, with less potential for disaster, to manage nitrates.
If anyone has had a true deep sand bed up and running for more than 6-8 years please speak up and tell us your experiences. I've only heard bad stories. A DSB for aesthetic purposes is great if maintained properly (providing routine aeration), but like John pointed out, several of the critters whom sift the sand will also feed on the pod and worm populations living there (another good reason for a remote sand bed!).
With the aquariums that I maintain I have taken over a few that have maybe .25 inch of sand on the bottom and the new ones that I setup with 3 inch bed I see more algae growth on the tanks with less sand then with a deeper sand bed.
How differently were the tanks maintained?? Grain size of the sand?? Differences in bioload?? There are a thousand and one variables that could have altered that interpretation but I think your interpretation is a very likely and legitimate finding. There is likely a decreased amount of microfauna in the 0.25in sand bed to manage the detritus and uneaten food. IMO a very shallow sand bed (0.5in or less) is the worst of all possibilities. It doesn't afford the microfauna enough room to populate safely out of reach of predators which will pick them off easily and keep their populations quite low. In a bare bottom there aren't those critters either, but often people are able to siphon out all waste in a bare bottom tank. Siphoning a very shallow sand bed is quite difficult and the detritus doesn't accumulate in any one area like in a BB.
Jeremy
