Yellow-green algae ?

[Wayne B]

Hi guys;

I am checking my own levels this year for the first time...my chlorine is 5ppm or greater (what is the downside of too high ?), alkalinity is 110 and solid, and others parameters are right on.

I add preventative algeacide each week....

And with all this....I still have yellow/green algea growing on the pool bottom, nothing on the walls.

As I mentioned above, I have gone heavy on both chorline and algeacide, but no luck......any advice ?