I have been using Leslie's Chlorinator tablets in a floater in my 20,000 gal pool. They keep the chlorine at a level where I only sometimes have to add some liquid chlorine. But the pH gradually drops to where I have to add base (soda ash) to bring the pH back into the 7.4-7.6 range. If I then take the floater out of the pool and just use liquid chlorine, the pH does not drop. I have not had to add acid to my pool for many months. Is that a problem with those tablets? Should I switch brands or just stop using tablets.