I am using a kit that uses drops but will only test chlorine and PH. I have ordered one of the good kits but have not received it yet. This is an inground vynal liner pool. Aproximately 20,000 gallons of water. Covered in the winter with a Loop Lock nylon cover.

I have had a problem with PH from day one. Using city water to bring the pool up to skimmer level along with whatever rainfall we get.

Using 3 inch chlorine tablets in a Hayward chlorine feeder. Shock the pool once a week with a powder shock packet bought at Kmart.

Filter runs continously, backwashed every week or more depending upon how many times it is vacumed.