A 6 year old bump, wow.
I've been throwing sand around and having it thrown at me for the last several years on several threads . Some sand people love their dsbs and the Dr . Shimek isms and fight for them zealously if illogically . Some still carry the" must have hypoxic or anoxic areas,euphemistically called anerobic zones" on to a spirited fight for plennums or remote sand buckets too. None of it makes any sense once an understanding of how the denitrifying bacteria work in the presence of oxygen and then nitrate and create their own "anaerobic zones" and the nutrients they need to thrive( organic carbnon, nitrogen and phospahorous), as well as the dynamics of water flow , advection, and the overall weakness of diffusion in moving nutrients in a dsb. Thereis little in teh dsb dialogue about these . The risks of anoxia and sulfate reducing bacterial activity are all but ignored by the dsb folks too. Fortunately, much of the time the deep sand is just sterile at least for some years since not much to sustan in the bacteria gets down there.
I started with the 4 inch plus deal,in my 90 gallon. Held on to it for 7 year anddefended it for teh first 4 . Afterall, folks like Dr. Shimek, and Anthony Calfo wouldn't steer me in the wrong direction ,would they?
As I added tanks to the system I used shallow beds (about an inch ; I like the beachy look. The surface area addition for the benthic denitrifiers is a plus too ,imo). Still I didn't remove the old dsbin teh 90. Figured if the dsb in the 90 was causing trouble, dilution would help as the system grew form 90 to 600 gallons. Still got nitrate problems though and some unfathomable coral issues, the dilution probably prevented an all out crash.
Once I understood that you didn't need depth ,just surface areas for denitrifing bacteria for dentirfication , a dsb seemed more trouble than it was worth.
Then came the real worries.
Once
i a learned a little about organics and metals and other stuff that build up and might release as the bed ages and localized ph shifts occur in the bed and anoxic anoxic areas form , my concern became more urgent.
Sure you can keep dsbs with new live sand replenishment, adding beneficial sand fauna ,whatever that is exactly , choosing only the right animals for your tank so as not to disturb the bed and on and on and on and on, but ,you wind up keeping a sand bed and telling folks that have trouble with them that they are doing something wrong like having sea cucumber or not having a seacucumber, or blowing off the top or not blowing off the top , orteh right or wrong kind of worms and snails .It is endless. I'd rather keep a reef tank.
Finally sucked most of it out over a period of several weeks. Tried a remote dsb,a whopping 7 inches deep; it did next to nothing for nitrates. Tanks improved once the old sand was depleted in the 90 gallon tank.
I do keep a few deep pools of sand 3 to 5 inches deep in some of the tanks for wrasses and the pistol shrimp which btw according to some would be poor choices for a dsb. So, I'm left to wonder why would anyone wan't one.
