I just want to recommend Seachem's Matrix biomedia for nitrate removal. For about 6 months, I have been using plastic bioballs in the back of my Aquapod. Even with weekly water changes, minimal feeding, and keeping a light bioload, I could never get my nitrates under 5ppm. At one time, I took a reading of 10ppm. I noticed that many people use Seachem's de-nitrate. I checked it out, and noticed that Seachem recommends a flow rate of no more then 50gph. Anything higher, and they recommend Matrix. So I bought 1 liter (enough for 100 gallons) to try on my 35 gallon system (sometimes more is better). I've been using it for 3 weeks, and now my nitrates are at undetectable levels. What sold me on this product is when Seachem stated that 1 liter (the amount I used) is equivalent to 10 gallons of plastic bioballs. This was music to my ears since I am always pinching for space in my nano reef. All in all, I am very happy with this product, and recommend it 100%. For more info check out
Seachem Laboratories: Innovative Pet and Aquarium Products . This stuff is hard to find. I bought it from petmountain.com for about $11.00 I think..
Excellent Nitrate Media 
