I am new to this site, and it looks like it will be very helpful. Please help- we have had our pool for about 9 years now. This year and last year we have had a terrible time with algae. We have brushed it all down, shocked it, used algecide, balanced it (using Leslies to test our water, I haven't had much luck with the test strips) and still can't seem to get it right. We also have had lots of staining on the steps and the liner. Stain out and metal out seem to help for a while, but it seems to come back after a few weeks. Our CYA level was tested at 90-100 for the last several weeks, so yesterday, we drained half the water, refilled it last night, and when we took another sample to Leslies, they said our CYA was still at 100. I am at a loss what to do here. (Does their test only go up to 100?) We are going broke adding chemicals and chlorine. We can shock the pool one day, and the next, the chlorine level is still at 0. After reading this site, I added 600 oz of chlorine to shock the pool. I plan to use some phosfree per Leslies recommendations. Here are our latest readings as of today (before adding the chlorine.) Any suggestions would be a great help to me. Thanks.
Total chlorine 1.5
12,000 gal, vinyl liner, DE filter