[spypet]

I went through this last year, and unfortunately the only way to reach Fert nirvana is to buy at least a Phosphate and Nitrate(NO3) test kit, since those are the two macro's most influenced by tap water, bioload, and plant matter. balancing them is most responsible for the good, like plants coloring up, and the bad, like algae blooming. It was not until I got a handle on these two macro's that I was able to keep algae from coming back, while optimizing my plants potential. You might want to ask in SnS if someone will sell you their year old test kits, since once you use them a few Months, you know your tank, and develop a feel for what it needs without having to test anymore, so the majority of these test kits go to waste.