stubborn algae

[hatavano]

Here's the scoop:
Summer of 2005 we had the 38 year-old pool revamped, including all plumbing to tile to gunite . . . we are familiar with algae and it's treatment. The end of the season (2005) we began showing some green staining. Shock/algaecide didn't work. This year it has doubled in growth, does not 100% imitate any circulation pattern, did not occur in old pool. Our pool company tested the water (chemicals and metal content) and it was normal. This discoloration is green **and has turned the rubber ends of all three filters green**
NEED HELP!!!

[kamkuda]

You have copper problems. You can test this theory but outting sodium bisulfate (pH reducer) in a sock and placing it on the stain. It should lighten the color.
ZThere are times that you cannot test for copper in the water and that happens when the metals have already plated onto surfaces. You shop get the water tested for metals anyways.