The depth of your sand bed will affect what benefits you see from it. If you run a bit shallow (a few inches 2-3) it wont be a functional sand bed like the deep sand bed, but it is easier to clean, you dont have to worry about accidentally disturbing it and harming the tank. You also can clean it pretty regularly. Now for the deep sand bed (dsb
) dsp's run several inches deep (5+) and offer the final step in the nitrogen cycle. A dsb
will convert nitrates into nitrogen, which can then be released from the water through surface gas exchange. Downsides to dsb
include you dont want to distrub the sand because it can release toxins and also kill off the good bacteria growing in the sand. Dsb
may foster algae growth to some extent as well. I personally prefer a dsb
because of the great landscaping it offers. As for sumps/refugiums, all of them are pretty close in design but keep one thing in mind, you want to keep the skimmer as far from the return pump as possible, this should prevent microbubbles. As for size id go somewhere from 1/3 to 1/2 the display tank size. As for algae id look at macro algae (caulerpa, chaeto, etc) each one offers its own benefits.