overhauled 125gal tank and still have problems help!!

[COB650]

My uncle has a 125 gal reef tank setup. It ran for 6 years and for the past 2 years he has been battling green hair algae. Me and him just recently siphoned out all the crush coral and cleaned all the rocks. Basically overhauled the whole tank. After this he is still has green hair algae problems. I checked all water parameters and they are in good standing except his PH which is 7.5 to 7.6. He uses super buffer and still can't get the PH to rise. Anybody have any suggestions.

Me myself I have a 100 gal and it's doing fine despite some nasty hair algae as well. But my all water parameters are in order.

[Randy Holmes-Farley]

What is the alkalinity?

Are you using tap water?

Have you measured either nitrate or phosphate?

[COB650]

thanks for the reply.

Nitrates are very low not even reaching 12.5 mg/l and phosphates are 0 and there is still algae growth?

When you say alkalinity are you talking about DKH? I measured DKH before the overhaul and it was at 3. I have to measure it again when I go over there this friday.

He is using RO DI water and he replaced all the cartridges a month ago so their shouldn't be any disturbance in that area.

Any other ideas?

[Randy Holmes-Farley]

With a lot of algae growth, the algae itself will reduce the nutrient levels. So if you detected phosphate, that would indicate a bigger problem, but reducing nutrients can still work. You just get them before the algae does.

If the alkalinity is really 3 dKH (not 3 meq/L), then it needs to be raised, and that may be part of the reason that the pH is so low.