Thanks for the reply. Sorry that I left out some pertinent info. It's a vinyl pool, 16 x 32. All summer I've not been able to keep chlorine in it, despite shocking every Sunday with the recommended 2 pounds and shocking every day in between with 1 to 2 pounds. I've been using dichlor for 2 1/2 weeks; prior to that I used calcium based. I'm not sure at all how the pH could have dropped so much. All I put in was the 2 bottles of algaecide (one with copper) and a total of 6 pounds of dichlor. The pump has been running 24/7 since I put the algaecide in. I didn't get the water samples off the top - I got them from about 10 inches deep. I had about 4-5 pounds of balance pack 100, so I just put that in to raise the alkalinity. I've not used any trichlor pucks. I don't have the past test sheets, but the CYA has not been that high until recently. Could the dichlor have done that? As I said, I've put a ton of shock in this pool in the last 6 weeks. The total hardness (I guess that is calcium hardness?) is 340.

Should I wait until the copper level has dropped to put the bleach in? I plan on getting another reading tomorrow, but they use Alex and don't have a way to gauge the copper reading.I tested the ph just now with drops and it appears to be right at 7.2, but that's with the cheap tester. I will get a good one soon! Assuming that the demand has finally been met (which may not be a good assumption), do I still need to keep the chlorine high for a while to take care of the algae? I have not seen any more; but I don't know when a safe period of time is to assume that it's cleared up.

Thanks for the help!