DSB Question

[sagxman]

I have read that a DSB will take some time before it becomes effective at reducing nitrates. Any idea how long it takes on average?
I have about 4" in a 29 gallon tank. I had 3" but read that 4 would be more affective and reduce the possibility of anything getting down too far and breaking the toxic barrier.
The bottom portion is medium grain LS and the top inch or so is finer grain non LS. Someone told me that the finer grain should be on top. Does this all sound good?

 

[beth]

A DSB is a lot more than just sand. You do have to develop the sandbed using detritovores, sand bed inhabitants. What is the particle size of your sand? What is your nitrite level?

 

[sagxman]

I don't know the actual particle size, but the bottom 3 inches or so is fairly coarse LS. The top layer is very thin "reef sand". Not live. Nitrite level is 0. Did you mean nitrate? If so it's around 20-30. But it's a new sand bed. I don't expect it to be perfect over night.