Originally Posted by
Murph
Well for what it worth sand beds is an area I have done some experimenting with. Tanks with deep beds 4+ inches, tanks with with beds a couple inches, bare bottom, nearly bare bottom with just enough sand to cover the glass and my current bed about a quarter inch.
The one thing that can be certain and anyone who has broken down tanks for moves knows vary well is sand beds get filthy no matter what degree of "live" we want to call them.
First off I have never had any problems when disturbing sand beds. In the case of deep sand beds hydrogen sulfide pockets will develop. If the sand bed is simply stirred I would imagine that these pockets could release into the water column but in the case of removing sand from the system FME the pockets simply siphon off and out with the sand.
In the case of removal or reduction of a sand bed and provided the presence of rock, filter media, a refugium etc. I have also never seen a significant enough disruption in bio filtration to produce detectable ammonia levels although evidently it is possible.
Right now IMO the ideal bed and in the absence of livestock that requires a deep bed would be my current quarter inch setup. Mostly for aesthetic reasons. A bed this shallow will not develop sulfide pockets and can and should be vacuumed. As was said, when doing this you can lose some sand. Adding a cup or two of new aragonite here and there to cover bare patches in the bed has not been a problem for me either.
I am also starting to believe that the nutrient sink that most unvacumed sand beds become is a primary vector for cyano growth. Especially when you consider cyano growth in tanks where other nuisance algae is not a factor, test indicate pristine water quality and all other solutions are being employed.
For systems where nitrate export of some sort becomes necessary, and given there is room in the sump, I use a remote DSB there. I use open unbaffled sumps. I have found that a tupper ware container as small as 8x8x4 filled with a mixture of fine grain and larger grain sands will function to export nitrates in systems with water volume 100 gal plus. With the DSB resideing in the sump and TW container it can quickly and easily be removed and or replaced or even just cut off from the display by turnin off the return pump.
This provides a safety factor for those that believe a dsb can crash. Personally I have never seen or heard of this happening any ware but on Internet forums.
At any rate this is what has worked for me. Your milage may vary.
well right now i have a hangon type refugium only 14inches long with chaeto what if i put in a deep sand bed in there would it benefit my 75 gallon at all