OK, I didn't have time to fill out the chart yet. FC=0, PH=7.0
There was a little algae on the sides which brushed off easily, mainly in the spa. I bought the 6 way HTH and took a sample in to the pool store and they confirmed all other levels were within range. I thanked them for not using the test strip.

It's very hot now in Sacramento, 100 - 104 the next 5 days. It's now or never for the stain removal. Deep breath... Last night I took out the filters, put in 2 lbs of powdered Vitamin C. sprinkled around sides of pool, let the pump run for 24 hours. Pool is 15,500 gals. After work today the stains were much lighter. I put the filters back in and am running the pump with the pool sweep. The sweep is on a valve, not a dedicated pump.

Now, how do I get chlorine back in?? I read don't shock but I don't know why? Pump is still running with filters in, but when can I add chlorine??? I'm going to have a serious algae bloom very soon. I know I didn't exactly follow your instructions but I don't know where to buy POP locally!! haha. When and how can I add chlorine? Thank you!!