How deep of a sand bed do you need to lower nitrates?

[jpucci1]

on avg what depth? I currently have about 1 1/2 inches to 2 inches of sand mixed with crushed coaral in spots.
I want to get some more to lower my nitrates but dont know how much to add.

 

[tangman99]

From what I understand, you need a minimum of 4 inches in order for denitrification to occur which is also the minimum depth to have a DSB.

 

[jpucci1]

4" seems like a whole lot of sand. is that true anyone can confirm this?

 

[finland]

Yes, for a dsb, to help finish the nitrification cycle(turn nitrates to nitrogen gas) you should have at least 4 inches of a fine grain sand. 4-6 inches is the norm on this board for a dsb. The sand needs to be that deep to have anaerobic bacteria for nitrate reduction.

 

[jpucci1]

thanks guys
looks like i need more sand. is the sand from here fine?
thanks

 

[krishj39]

the sand from here is fairly fine, but also mixed in with larger pieces, like the size of crushed coral. just to clarify, the sand needs to be that deep because the bacteria that change nitrates to nitrogen are an-aerobic, which means they live where there is no oxygen, so they have to be deeply buried in the sand.

 

[thomas712]

Actually you can accomplish this with less than 4 inches if the sand is fine enough.
Thomas

 

[justinx]

I second Thomas on that. I use sugar sized sand, and i have LESS than 3 inches in some spots. Yet to see any trates show up on the ol' test kit. (I have even tried a second test kit to make sure mine worked)

 

[jpucci1]

thanks for the help guys!
I will add more and see how it goes. I would like to know how long it takes to get it going.