Hi, Steve,

Your call on which Cl source to use...Cal Hypo adds a little calcium to your pool and I didn't see you post test results for it...probably not an issue if your Ca is below 400.

So go back to my first post and get your Cl level up to the 15-17 range. The important thing is to keep it there...probably for 24 hours or so AFTER you detect no sign of the algae.

Then be sure not to let your Cl slip below 3 for maintenance. I'd try to keep it between 4-7ppm.

You may certainly use polyquat. Many folks have good success with it. I have never used it and, so far, I have been able to keep my pool clear with chlorine only.

I have never seen tablets that do a Cl tesst so I cannot comment.

Post back and let us know your results.