Green agar with zero PO4?

[A.G]

Would some one explain this to me.

I had 0.04 po4 on hanna with no algae on the glass , week later algae started to grow on the glass and I get zero reading on hanna ulr checker.

So if algae is consuming the PO4 and its locked inside the algae, why do i get browning on my corals ?

I really can not understand this .

 

[Craigdillman]

browning on the corals can be from many reasons other than high p04, my phos is low like 0.06 and i still have to clean the glass. What are your other parameters