Nitrate ?'s

[MaineReef88]

Hey guys I have a question about Nitrates.

All the levels in my tanks are great other than the nitrates.
Here is my question -

The Nitrates of my 90g (and 56g) are at 20, What I want to know is how "bad" this is?? I know they should be zero, and they always have been. I am doing 10% water changes, but they havent come down yet, (they did come down from 20 to 5 in my 12g nano after several changes)
I have done two 10% changes in the 90 so far since I have noticed the rise in nitrates. Should I continue this? or change more?
Again I just really wanted to know what the effect of a level of 20 has on the fish, inverts, and coral. I want to get it fixed asap, but I dont know if this is a detrimental fix, or if I have some time to work at it.

Thanks so much!

[2thdeekay]

Here's a good read, in case you haven't found it already. :)

Nitrate in the Reef Aquarium
http://www.advancedaquarist.com/iss...st2003/chem.htm

[tmz]

20 ppm isn't likely to do much if any harm . It might feed a bit of nuisance algae but if phosphates are low it shouldn't be a problem. I aim for 10ppm or less.

[MaineReef88]

Thanks that makes me feel a little better.
I was worried because it has always been zero believe it or not,
as i only has 3 little fish in a 90, now I have 7.
Thanks