In response to poolbuoy - no I did not use any Algaecide? I thought you should only use chlorine to kill the algae. My pool is starting to change for the better as I desperatly needed CYA. Now the chlorine is holding and the color is looking much better.

My new problem is similar to the last part of this thread. Sand in the water by the return jets. A couple of weeks ago, it was just a little sand. Now I've got at least a cup of sand by all three return jets in the pool. Clearly something wrong with the filter (Jacuzzi - ST24) - but what? How can I test where the problem might be?

I posted this question under the Pool equipment section, but no answers so far.