Deep Sand Bed

[Desktopflame]

Hi,
i have now been running a scrubber for just under a year and have been skimmerless for 6 months. I have had a dsb in my sump for 2 years and have never seen my nitrates below 20. After installing the scrubber they went down to about 5 but have been gradually increasing over the past few months to 30 now. I have noticed a black layer in my dsb about 2in down and am wondering if this is the cause of my high nitrates.
My local lfs told me to stir up the dsb but I was under the impression they shouldn't be disturbed.....so question is do I :-

1,stir up the dsb in the hopes nothing worse will enter the water
2, syphon a bit of the sand bed up
3, completely remove the dsb
4, something else?
Thanks in advance guys

[rainerfeyer]

I am no expert by any means, but have been following the DSB topic for the past several years, wver since seing Anthony Calfo at a Reef meet.

Though it seems to be a great idea, and apparently very effective, it does seem to have it's drawback in the 'maintenance' department - i.e.: It takes a lot of maintenance. Apparently the sand should be replaced every several years. One thing I do read over and over is: NEVER stir up the sand, as there are far too many bacteria which can and will be toxic.

It seems, drawing from the experience of others, to render to the question: why do we still need a DSB with an ATS?

Myself, have been without ozone, without PS for months - and the tank never looked better!

Rainer

[jgreen1025]

Like Rainer, I don't think you're supposed to disturb DSBs, especially if they've been in place for any considerable length of time. Plus, unless I misunderstood, it's only conjecture that this dark band is the reason for the elevated nitrates. Are you sure there isn't something with the scrubber that has changed or that you're doing differently? I'd look at all other possibilities first before making such a drastic change in the system.

What kind of critters do you have in the DSB? Do you have any snails such as nassarius that burrow into the sand? What about worms? My understanding is that for a sandbed to be truly healthy it needs the normal complement of worms and stuff that will constantly 'disturb' it in small amounts.

Here's a few articles I found helpful in case you haven't already read them:
Food Production By Design, How A Deep Sand Bed Can Produce Food For Reef Inhabitants
How Sandbeds Really Work
Nassarius Snails as Scavengers in Reef Aquaria

[Rossco]

I would guess that you are not getting enough flow across your DSB and that there isn't much living in it.

[new2scrub]

If it was me I think I would start siphoning out small amounts of sand every week untill I had a "normal" sandbed If my scrubber was working properly .