Well my nitrates were never what I would consider high, usually aroun 10-20 ppm, but within a week I tested and I was getting 0 ppm nitrates after adding the chaeto. I use a small 13 watt pc light, the kind you can find at a regular store used to replace like a regular 60 watt household bulb... nothing fancy. My HOB filter isn't to big either, I am actually using one side of my millenium 3000 filter. I usually keep a small handful of chaeto in it and when it doubles I take it out and pull it into two parts, put one part back in and throw the other away. I know alot of people sell chaeto by the sandwich bag on those auction sites.. or you could ask around on here to see if anyone in your area would mind giving you a handful of the stuff..