Exact problems when mixing a deep sand bed?

[SkinnyPete]

What will be the possible problems with stirring up an established DSB?

I'm re-aquascaping a 110 gallon for seahorses. I have 3 large show pieces of live rock, they're about 16" long. Right now they are stacked sideways. What I'm trying to do is stand them all up and build columns instead of shelves, to leave more sand for macroalgae. So, I was planning on digging a large ditch in the sand in several places, sticking the rock on the glass bottom standing up, surround it with base rock to hold it upright, then cover it back up with 4" of sand bed. My tank parameters are really nice right now. My nitrates are about 5 and I'd hate to really screw things up at this point.

So, if I stir the sand bed, what is the worst thing that will happen? Is it just Nitrate? Will it be noticeable immediately? Any way to avoid this? Will a huge water change correct the problem? I do plan on housing livestock in a seperate tank while this is all being done.

Thanks.

- Skins

[GuOD]

I've heard it's very bad to disrupt a DSB (same reason you don't transport it from 1 tank to another). Lots of stuff underneath will affect stuff I think.

[roka64]

There tend to be dead air pockets that can be filled with ammonia or other nasties. Personally, I would do one section at a time, maybe 1/3 of the tank, have some premixed water in the event of your water fouling. Test, test, test.

+++EDIT+++
Those seahorses might not get along with your current inhabitants. They are best kept in a species only tank.

[SkinnyPete]

Thanks for the quick responses. It can absolutely be done gradually. There will probably only be 3 spots that I'll really need to anchor into the sand bed. Maybe a 6"x6" footprint in each, into a 4-5" sand bed.

So, test for ammonia and nitrate? I've read about sulphur dioxide being released when stirring deep sand beds. Do we think I need to worry about that with only 4-5"? It has been up for 2 years.

[roka64]

Hmmm, not sure about the sulphur dioxide. I think, if you go slow and one section at a time, in that sized tank, you should be ok. I would wait for other's input.

[Kurt_Nelson]

Actually, the concern is Hydrogen Sulfide (H2S) gas pockets being released into the tank. If you research it enough, you'll find good arguments on both sides of whether or not it's really a problem. When I was researching DSBs, it seems that while there's anecdotal evidence regarding H2S causing problems, there really isn't any hard and fast evidence of it causing problems. If you read through the DSB articles over on wetwebmedia.com you can probably draw your own conclusions regarding it. Personally, I decided it really wasn't a concern.

[melosu58]

Originally Posted by Kurt_Nelson

Actually, the concern is Hydrogen Sulfide (H2S) gas pockets being released into the tank.

The ole rotten egg smell. But I would do as Scott said and remove it in sections. You are going to keep just SH`s in this tank right?

[SkinnyPete]

Originally Posted by melosu58

The ole rotten egg smell. But I would do as Scott said and remove it in sections. You are going to keep just SH`s in this tank right?

Thanks, as usual, all.

Yes, species only-ish. I've done my research. Actually, I plan on a few captive bread horses, plus my mandarin - down the road I may attempt a pipefish or two, and a Hawaiian Dragon Moray (kidding). A local fish store and some reefers near me have trained pipefish on frozen foods pretty successfully, so I might give it a shot down the road.

I should have plenty of rock and pods, plus a mature fuge to sustain captive bread seahorses eating frozen and the mandarin (had her for 9 months now). Obviously, I'll just have to keep an eye on the mandarin and the pod population. I'm looking forward to it.

I should mention ,before someome chastises me , that I'm aware that there is a lot of pipefish/seahorse compatibility controversy. Seems like the thinking is that they should not mix, although many people seem to have success in my local reefing club, which is why I say "down the road" on the pipefish. Still not sure on that one.

- Skins

[melosu58]

I dont have an idea on the pipefish but as far as the SH`s My captive bred ponies eat frozen mysis like it`s going out of style. My LR has pods in it but nowhere enough to feed them. I dont have to worry because they love frozen mysis. But your manderin is another story. By the way you had me going on the dragon moray. LOL