Hey I'm new to this forum, however I found and used this site last year. I have not posted any questions on here yet. I just wanted to tell you that last year I got tired of the stores telling to buy this and that and their test did not make since. So anyway I found this site and just read and follow the instructions here and I had the best season ever with my water. The steps and products they tell you on here WORK and work well. I couldn't be happier! And opening my pool this year was a breeze compared to years past. So bottom line from a dumb ol' country boy, forget anything they told you at the pool store and follow the instructions on this site. You will be glad you did. I see why they called this site "Trouble Free Pools" and you will too!