Here's an interesting patent that shows tests completed with results when using PCL as the solid organic compound for nitrate reduction in aquariums. Some of the info may prove helpful to some hobbyists who want to DIY. It's interesting that they achieved good results by placing enough of the PCL in a filter bag. It's also interesting that placing the PCL in a course bed medium works well and the PCL only needs to be added once or twice per year into the bed. Maybe crushed coral will make a comeback.
Denitrification of aquarium waterG Ritter - US Patent 7,244,358, 2007
http://www.freepatentsonline.com/7244358.pdf
Real Reefers Use DIY.