Need help id what is in my tank

[Mike Nguyen]

So my tank is 6 months old now. And this algae or idk what should i call it appeared and growing in the back of my tank, they are light brown color. I did scrubbed them away and siphon out as much as i can but i will come back in 1-2 weeks. Problem is they will be appeared/growing overnight. I try to bring my po4 down and it did not help. My system is a simple system with weekly water change, light 8hours a day 4 Hydras 52 hd, tank is 200 gallon.

 

[Mike Nguyen]

Up.

 

[saltyhog]

What are your parameters? Does it blow off the glass/overflow easily with a turkey baster?

 

[Mike Nguyen]

What are your parameters? Does it blow off the glass/overflow easily with a turkey baster?

My tank is at 1.025 salinity, temp at 26 celcius. My tank now only stock with some Zoas that is why i do not check Ca Mg or Kh. 800 liter in total and i do water change 80 liter every week. Running rowaphos and biopellet reactors. It does not easy to blow off by turkey baster.