How deep should a DSB be?

[fishykid9212]

I have a 30G hex and I am going to stock it very llightly, How deep should I put the sand to control nitrates? also does it have any negative effects? Such as a phosphate maker or does it help get rid of phosphates? thanks

[Johnbob]

A deep sandbed should be at least 3-4 inches deep to form the anoxic zones necessary for full processing of the nitrates. It can be as deep as 6 inches or more if so desired. A lot depends on what animals you will be stocking that could disrupt the deeper parts of the sandbed such as burrowing fish, e.g., jawfish or engineer gobies, the latter which are constantly reconstructing new burrows. As far as phosphate goes, it is mainly derived from feeding, not your substrate. Dosing kalkwasser, growing macroalgae and using a phosphate adsorption matrix are your best ways to export phosphates.

[fishykid9212]

OK so if I used 3" caribsea arogonite that would work? I don't like the deep sand look so the lower it is the better, but I also want it to work. I will probably have a clownfish or two and another small fish, no burrowing fish though.

[A.G]

the smaller the grains( less than 1 mm) the better if you are going with less than 3" deep.
you could still have dinitrofication in 1" sand bed if the grain was very fine ( suger size). HTH

[cweder]

Aragamax or Arag Alive Bahamas are sugar size and excellent for nitrate reduction. Still recommend at least 3 inches though. Be sure to cure your rock before adding the sand or the sand can load up on the phosphates from your curing rock so I've been told.

[fishykid9212]

I believe my sand is this stuff here, but it cam in a bigger bag, also my rock is already cured, it is from a different tank and I used some of the sand from the other tank also. Will it still work with this stuff?
http://www.petsmart.com/global/product_detail.jsp?PRODUCT%3C%3Eprd_id=845524441810938&FOLDER%3C%3Efolder_id=282574488339119&bmUID=1155655756984

[Johnbob]

Yes, that should work, especially if it is the sugar-fine grain size. You need to use the small stuff to get the anoxic zones formed. Larger stuff such as crushed coral only becomes a nitrate factory because the oxygen levels remain too high to support the bacterial species capable of utilizing the nitrates as an energy source.