Yup, I've got the KNO3. Been dosing to keep nitrates at 10ppm

Oh, yea. A phosphate test showed levels off the scale immediately after
the 50% water change. I don't understand that. I can only assume the
test is accurate. It reads 0-0.25ppm for my tap water.

my aquarium page, info and pics at:
www.geocities.com/spiral_72/Spirals_page.html