New growth causing lack of color?

[Craigdillman]

I'm guessing if you have algea like that your po4 isn't zero what test kits are you using, most kits are very inaccurate at low po4 levels and are very hard to " tell what shade of off light blue is this stupid vial compaired to the paper" ,

I bet if you had a Hanna checker you would see the po4

Regardless I would still run the rowa and try to manually remove as much as you can and It should start to starve it out, manual removal is best at the start then work on starving it out and not giving it the nutrients it needs ---> via gfo/rowa and water changes

Good luck man it will come around