Hi all. I have some staining on my pool built almost a year ago, so this was our first summer. I have some stains on the bottom of the pool and upon closer looking, I noticed the sides look different than the bottom. Determined that the stains disappear with Vitamin C (I was able to write "HI" with the tablet on one wall of the pool). I'm ready to buy the asorbic acid and complete the treatment. I don't know what is causing my stains. I had my fill water tested by my local pool store and the report said the iron and copper were barely out of range (I forgot to bring my results with me to work today so I could post those), and I looked at my water source's water quality report and I didn't see anything out of the ordinary. Are sequestrants the way to go as far as preventing stains in the future or do i just see what happens if I keep my PH on the low 7.2-7.4 side? If yes to sequestrants, I have these questions:
1) What do I buy?
2) How often would I use the sequestrant?
3) Do I keep the sequestrant in over the winter? My pool is not covered so i test the ph and chlorine every week or so during the winter and adjust as needed.
4) I read about sequestrants leaving behind phosphates so I would have to eventually treat for that. Is this correct? Isn't phosphate treatment a pain in the hiney?
5) Anything else I should be aware of/be thinking about?
Thank you for your help!