I have mustard algae so I double-shocked the pool. It turned from blue green to milky blue with yellow algae on bottom. I took a water sample to the pool store the day after I shocked it. Here are my pool store readings:
Please note that last week everything was normal except the CA, which the pool store told me to add more of.
Here is what the pool store told me:
"You have CHLORINE LOCK!!!! Do not add any tablets for 30 days! It looks like you have been using chlorine from WALMART!!! I said, "no, I have been using only what I bought here" They told me to use "another source" of chlorine. (??) I told them that my numbers were normal until I added the shock that I bought from them. They also told me my CYA was too high and I would probably have to drain the pool and put new water in it. They also told me to add copper algaecide, which I told them I am scared of because it might stain my liner. They replied, "But the kind *we* sell is copper CONTAINED. It won't stain the liner." (Note; I didn't buy any.)
In the meantime, I still have yellow algae that I have been brushing and vacuuming to waste, but it doesn't seem to be going away.
Can someone please tell me what to do? And what is "chlorine lock"?? Will I really have to drain my pool?
Thank you in advance for your help.