Lighting question

[MizTanks]

I have zoas/palys/kenya tree and favia~what's the shortest amount of time I can keep the tank light? At the moment I have em on for 9 1/2hrs~I'd like to cut it down to see if this would slow the algae growth down if not kill it.

[ryeguy28]

i do 7ish hours a day and i still have brown algea

have you checked you phosfates ?

[MizTanks]

I get .0 readings of phos from using the API master kit~which I'm told is unreliable~just really wanted to know how low hour wise I could go without hurting my corals.