Thank you for your response. I'll get the materials and follow your advise. Just to clarify,the spa flows into the pool and both are on the same system unless I select spa then only the spa is connected to the system -pump,filter,heater,SWCG. Otherwise in non spa selection the spa is 1 of 5 Caretaker returns to the pool/spa. I currently have to add a quart to 2 quarts a week of muriatic acid. I read an article that said some pools can have a higher PH, (up to 7.8 or 8) then normally recommended and not have any problems, but can not find any info as to weather this works if you have a SWCG. Do you have any comments on this?