Why would TA fail to go down after adding a cup of Muriatic Acid to a tiny 1200 gallon pool? My TA was 200 ppm when I added the acid yesterday afternoon, but this morning TA is still 200 ppm. My pH dropped a lot because of the acid addition, so why didn't the TA drop along with it?
I set up this very small 1200 gallon above ground Intex soft-sided metal frame pool about a week ago. The nearby shade trees prevent direct sunlight from hitting more than 30-40% of the pool surface at any one time. We seldom use the pool so I keep it covered with a large sheet of vinyl (from a billboard) most of the time. The cover rests on 90% of the water surface, dramatically reducing the air-exposed surface area.
I filled the pool with tap water then added regular chlorine bleach for the first few days of use before I got my test kit. I have not added any dichor/trichlor/cyanuric acid so my CYA is probably zero -- unless CYA is a component in my local public water supply?
I currently use the $15 test kit from Home Depot so I also bought this Blue Devil CYA Test Kit from amazon.com which should arrive in a few days.
My overall goal is to bring my TA down to 80-100 ppm, then aerate to bring the pH up to 7.5, then add enough dichlor to bring my CYA level up to about 50 ppm. Then when everything is stable I plan to add Boric Acid as an additional buffer / water conditioner. After all this is done I should have a relatively stable pool that requires only small amounts of bleach to maintain the correct FC levels, or at least this is what some websites suggest.