Sand: how much is too much?

[gasmonkey]

Ive heard different opinions about sand, some people sand the more the better, at least 2 inches, and some people say only 1/2-1" max because nitrates and ammonia and stuff decomposing under the sand with very little oxygen can produce toxins that can kill your fish. I have a 65 gallon tank, bottom measurements are 36" by 17", Im getting indo-pacific black sand from carib-sea (its agronite, not plain sand), and was wondering what is the optimal amount and what is the maximum amount to put in?

Also, ithe sand is sealed in a bag with seawater, so it will help my cycle, but in one other thread it said to wait until the tank is cycled to put sand or rocks in, can someone please explain this in a little greater detail? somthing about shrinking I was just slightly confused.....

Thanks

 

[mogurnda]

There's a lot of opinion, a few experiments and mostly confusion about sand beds. Deep sand beds (>3") supposedly develop a hypoxic area that allows bacteria to convert nitrate to N2 (or maybe NO, depending on the "expert" you ask), which then bubbles off. Bare-bottom tanks allow the removal of debris from the bottom, and some think this is a better way of reducing nutrients. Supposedly (again) in-between depths are the worst of both worlds.

I have run tanks with shallow sandbeds (about 1-2") and deep sand beds (about 5") and they have been perfectly healthy for years.

I am not certain what was said in the other thread, so I will probably confuse the issue further. What I would do is buy some base rock, put it on the bottom, and then add your dead sand. Having the rocks resting on the bottom of the tank (and not on the sand) means that the rockwork will be more stable when things dig around. Over this, add the bagged live sand. Then add some seafood to rot and get the tank cycled. After this, add some good quality live rock to top off.

If you were adding top-quality, freshly shipped live sand, I would put it in after the cycle, to keep the life from dying in the cycle. The stuff in the bags is so compromised it doesn't matter as much.

 

[gasmonkey]

Thanks Mogurnda, kinda clarifies things. I got 80 pounds of sand in today, but Im doing all live sand, its black and white, so I didn't feel like looking for regular black sand of the same consistancy, so I put 40 pounds of sand in, and when its cycled Ill put the other 40 in. (it is supposed to help with my cycle since it has all that seawater bacteria) and it has only been bagged for 6 weeks, so yeah, but thanks I appreciate the help being a newb and all,