LS question...help!

[cholland]

Here's my scenario first before I ask my question....
My tank is a 55 gal FOWLR. I am slowly moving toward a reef. I have always had nitrates in the 40-50ppm range. I recently set up a 10 gal refugium, but it is not effectively lowering the nitrates yet. It has been up and running for 2 wks. But when I questioned a local hobbyist about my nitrates. He stated that my LS bed should be lowering the nitrates. I told him that I have 3-4" bed that came from the FL keys. It is fine grain.
So is there something about my sand bed that is not working?
Does it need more critters or something?
The tank has been running for almost 2 yrs. All other water parameters are fine, at 0ppm.
Any ideas????

 

[nm reef]

A properly established and maintained DSB can indeed reduce nitrates...and critter diversity is vital(in my opinion) to a functioning DSB. I try to insure adaquate populations of pods/worms/snails/crabs to boost the effectiveness of my DSB...there are a few on-line sources for kits or packages to help you DSB. I've never used them...instead I've depended on quality LR to provide diversity and the addition of other types of material to boost micro infauna. My favorite source of diversity other than LR is crud/rubble from the bottom of tanks used to cure large amounts of LR(ck with a LFS for this source).
As for the refugium...if it is properly established and maintained it too can help with elevated nitrates. especially if there are macro algaes being used to consume and export excess nutrients.

 

[cholland]

I agree with everything you said, but I heard that certain depths or kinds of sand are more condusive for the process of denitrification.
Like a 3-4" bed is better than a 1-2" bed and so forth.
I am of course waiting to see if the refugium makes a difference as well as trying to control the other factors that can affect the process. And then maybe try to get some more critters.