I have been getting some green hair algae in my tank.I have been removing it by hand ,as much as possible .I know algae grows from nutrients provided by high nitrates and high phosphates .My nitrates are less than 10 ppm, and I have added a phosphate sponge .Lighting also makes algae grow .So I going to remove all the algaes needs.My question is "What is the least amount of time that I can run my lights a day and my corals still stay heathy?"