High Nitrates
Hi Bob!
<Howdy>
I use your brilliant site a lot and have a copy of your excellent book but I can't see anything relating specifically to reducing high nitrate levels.
<I need to write, post a definitive series of expository statements re the topic... for marine, freshwater, pond... In the meanwhile, have been accumulating input and archiving it in a couple of FAQs files: http://www.wetwebmedia.com/no3probfaqs.htm and the link at top>
Since becoming the proud co-owner of a 75 gallon (98 US gallon) reef tank 6 months ago, things have been going quite well. The water levels are all fine (ammonia 0, nitrites 0, phosphates 0, SG 0.123, pH 8.2, dKH 12, calcium 400) except the nitrate level. No matter what we do, we just can't seem to get it below 80ppm (I can see you thinking "yikes" as I write!)
<Yes...>
After reading some info on your site we started using PolyFilter alongside our other filtration methods (Eheim biological filter, Eheim canister filter with activated carbon, phosphate and nitrate medium, protein skimmer and UV sterilizer) but the levels will not budge.
<Time for more action in the "opposite" (denitrification) reaction series... Do read through the other links on the FAQs file above... on the use of macro-algae, DSBs, denitrification, live rock...>
The fish, corals and invertebrates all seem happy enough and, in fact the Goniopora corals (yes, I know these are not a good choice but did not find that out until after we bought them, having consulted your site) appear to be thriving!
<Yes!!! This is their "natural" setting... that is, they do appreciate higher soluble organic, inorganic "fertilizer"... This is the principal reason most folks have such dismal success in keeping "flower pot" corals... their systems are "too clean".>
Is there anything you can recommend to help us reduce the nitrate levels back to <10ppm?. 
<All sorts... as stated above... please follow the links, parts of the site listed as you read through the various FAQs... a sump/refugium that is lighted, with macro-algae... would be ideal... but/and there are other approaches to augmenting uptake, biological denitrification that are worthwhile>
We have since realized that we have overstocked somewhat and are working on getting a 200 (UK) gallon aquarium ASAP to alleviate this and I suspect this could be contributing to the high nitrate levels.
<To an extent, yes>
I won't list our entire livestock here as I don't want another "yikes" - one is reprimand enough! :-)
<Yikes! Sorry.>
Meantime, I would be very grateful of any assistance you could provide to reduce our nitrates for the time being until we are able to get the new tank.
Keep up the good work and thanks!
<Will endeavor/endeavour to do so.>
PS my husband loves scuba diving too!
Lesley
<Brrrrr, hopefully in the tropics, not just "off the coast"! Bob Fenner>

High Nitrates, Large Letters 
I have a 55 gallon salt water tank fish only, nitrate levels are at 140ppm. Running a small wet and dry filter, protein skimmer, Eheim canister, 4lbs of carbon., 50% water changes every four weeks and nitrates are still at high levels. Would adding live sand and bio balls help?
<Yes to the live sand... no to bioballs... Do consider more live rock, macro-algae, possibly adding a refugium... maybe with a plenum there... increasing aeration, ditto Redox by ozone, uv use... Take a read over the Nitrate area on the www.wetwebmedia.com site>
Thanks Louis
I was not aware that caps meant I was shouting sorry was not meant that way.
<Oh, and not to worry. Not admonishing you (have mercy!), but the "shouting" term is Net-parlance... Appreciate the re-keying... much easier to read. Bob Fenner, the bleary-eyed pet-fish man>

Live Rock, Nitrate
I am very new to saltwater tanks, and I have a few questions.
<Okay>
First off I have a acrylic hexagon tank (about 18 gallons) with one porcupine puffer, about 4.5 inches long, and one blue damsel. The porcupine puffer is a very messy eater and the damsel doesn't seem to help much.
<Not "its" job>
Do you know of any small scavengers that wouldn't be eaten by the porcupine puffer?
<Not really... in this setting... the size, shape of the tank... are too limiting... it's too small for the puffer alone in reality>
I have about 1.5 pounds of live rock. I was wondering if it really does remove nitrate from the water, and if you would recommend getting more live rock.
At what nitrate level do you recommend doing a partial water change?
Thanks,
Ariel
<More live rock would help, and I would do regular water changes (likely 20-25% every two weeks, with pre-made water... Please read over the following parts of our website on water changes, puffers...:http://wetwebmedia.com/diodontpuffers.htm, http://wetwebmedia.com/water.htm
And live rock, nitrate FAQs...
Bob Fenner>