Here is some background info:
I bought my house last May and became a pool owner for the first time. The day I moved in, I called a man who does pool maintenance to come over and give be some training on my pool.
He deducted that the previous owner used tricolor as a sanitizer exclusively. My PH was well below 7 and there was no chlorine at all. Other than a small area of green algae under the pool ladder, the water looked good.
He serviced the pool and his instructions were to shock the pool with cal-hypo 65% when the color on my test kit registered 1.5, and he estimated that to be about 2 weeks. I tested about 3-4 times a week, and about 6 weeks later my chlorine was still over 3. I decided to go ahead and add shock anyway because the floor of the pool had some slippery areas.
Finally in the late summer/early fall I determined that my CYA levels were very high. They were well over 100. I quit using trichlor as a stabilizer in late Sept. and did not use any all winter or this last spring.
Currently the only problem I am having is with mustard algae. It appears for a few days immediately after I add shock. However, it is always present on the steps in the shallow end.
Is this thriving or dead mustard algae?
Because of my high CYA, I would need to use a ridiculous amount of chlorine to kill it. So instead, on Monday I used Bioguard MSA algicide with copper, and then shocked again immediately after adding the algicide (that is what the pool store folks told me to do).
My questions concern the correct usage of the algicide. I don’t know if it killed the mustard algae or not. Today (Wednesday), I went to the pool store to ask if I need to add more algicide, and was fortunate enough to speak to one of the pool maintenance guys instead of the usual high school kids at the counter, and he said “don’t use anymore algicide, it is dead”.
I don’t know if I should accept it as true or not.
My readings before adding shock on Monday were:
25,000 gal in ground , vinyl, cal –hypo 65%, trichlor, polaris.