New member. Apologies if this should go to another section - the description suggested this was the area for discussing stains.
My pool: 20K gallons, plaster/gunnite, DE filter, trichlor.
My numbers from testing at Leslie's:
I know that Leslie's testing may not be the most accurate. I tested with a strip also (again, not the most accurate) and the results are somewhat consistent.
I also have brownish/light tan stains on the floor of the pool, mostly in the deep end. Occasionally, over the past year ( but more as the weather in TX started to get warmer) I have noticed a light tan film on the plastic/vinyl parts of my Polaris cleaner or the drain covers. The metal rims around the lights used to be shiny, but now are brownish.
I'm not sure whether my problem is calcium scale, organic or metal staining... so I'm even less sure of the solution. The pool calculator suggested draining and refilling my pool 35-40%, as well as adding baking soda to increase TA.
Draining and refilling water is an expensive option. Can I neutralize the chlorine with sodium thiosulphate? Do I need to lower the pH further?
Your recommendations would be most appreciated. Thanks.