Hi all, I know that we are all concerned about our inhabitants' environments. I have been kicking around the idea of saving a few scheckles by DIY equipment. I have been pretty successful with an HSA style protein skimmer, and sump. Well worth the work. But has anyone done a DIY coil denitrifier (sp?)? I would like to build one, but I would like to get the opinions of those that are more in the know than I am. I typically do a 10% changeout weekly. Any and all opinions, gripes complaints and pre-conceived conclusions are welcome! Thanks in adv.