pt 2 is in the tank 2 weeks. i have not added anything yet. yesterday the nitrates read 80ppm with a new api test kit. changed about 30% of the water. today it's still at 80??? any ideas. po4 was reading about 5ppm. i,m using ro water btw. just powerheads, and a skimmer. and i have a hang on with carbon only, no pads