Hi,

I have a 75 gallon planted tank and have recently started getting green hair
algea growing on some plants and on some rocks. My plants are doing great.
I have a Coralife compact flour light 4 x 65 I think it is. Well, I bought
a Tetra Phosphate test kit and the blue is so dark it's off the scale. I
don't understand this. I do 2 water changes a week. Each one is about 5
gallons. I use some of the Florish products weekly. for filters i have an
Eheim Pro canister and a Magnum 350 that I use to run different filter media
in. I usually use Purigen. I get good effects from it. The only other
thing I have used is some stuff called "Instant Amazon". It says it doesn't
support algea growth, but I am starting to think otherwise. I have stopped
using it until I stop the algea. Oh yeah, my lights are on timers and I had
the lights running about 13 hours a day. I know that is probably too much.
I have reset the timers to about 10 hours a day. How does that sound?

Why do you think my phosphates are up? I did about a 20% water change today
with water that airated overnight, but the phosphate levels still read as
high. Do you think the reading could be false? I also have a SeaChem PO4
test kit. I take a test with that one and see what it indicates.

thanks for any advice and reading all my questions.