Algae

[carib swim]

Hi guys and gals,

Haven't been here for quite a while because my pool has had no problems. But now im back.

My pool chem parameters are all perfect. My water is cristal clear. But there is a recurring algae problem. After a few days, on the bottom of the pool there appears a thin film of powdery algae. I then vacuum the algae to waste and after a few days the thin film reappears. I even upped the chlorine FC levels to 10 ppm. As is said my pH level is 7.5 so this is a good range for my chlorine to work. TA is 120. Every pool chem parameter is also perfect. Ch is 100.

Please help meeeeee!!!!! I don't like this green stuff!

[chem geek]

You didn't list your Cyanuric Acid (CYA) level so you can't say that your water levels are in good shape. Also, with your TA of 120 ppm it sounds like you might be using Trichlor pucks/tabs. For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases CYA by 6 ppm. The CYA builds up and lowers chlorine's effectiveness unless you proportionately raise your FC target.

In previous posts it sounded like you were using bleach as your chlorine source so I'm confused. What are you using? Also, are you sure the powder is algae and not dirt, perhaps from a broken filter? See if you can collect some of it -- if it's slimy it's algae, squishy it's pollen, hard/rough it's dirt/silt. Looking at it under a microscope would be definitive.

For shocking the pool for green or black algae, raise the FC level to 40% of the CYA level and keep it there. If you have yellow/mustard algae, then the FC needs to be 60% of the CYA level. Read Defeating Algae and/or Mustard Algae.