Alright well i have a question for all who can answer. If my nitrates are as high as 10-15ppm.. then shouldn't there be like a mass amount of algae growing? I have almost NO algae growth in my tank. Only a little bit of algae started growing on one of my rocks, and it's about the size of a quarter.
I usually wait till around 20ppm to do a PWC, after the PWC it gets knocked down to about 5. Are you talking about the green, brown, redish, purple & Pink stuff all over the tank?10-15ppm isn't as high as you are describing it IMO. Just wait a while and you will be going through a cycle of all kinds of algae lol, best I could describe.