IMO, if your going for an anoxic area, save yourself the hassle of making a plenum and just make it a solid DSB.
I agree. With a DSB
, its just glass, sand, then rock, NO mesh. A plenum, although not a terrible idea, is less stable then a DSB
.....as you would naturally assume being that they are not natural occurances. I have read a TON of reports about plenums failing after a short (couple of years) time, and leeching posphates and nitrogen based chemicals back into the tank, which is usually devastating to the tank. They use a plenum at the LFS
in their bad *** reef display, but it has a tube sticking out of the sand to allow for at least some water exchange. A plenum is like a UGF
, but more constricted. I personally chose against a plenum for my new setup, and went with a 5" DSB
, and my buddy did a plenum in his at the same time. It may be coincidence, but he is not seeing the nitrifying process like I am, and he continues to have raising nitrates...........as of a couple of weeks ago. I should check in on him and see how its going. HTH