Hi, you answered a question for me a few weeks ago about our cloudy water after opening, and after giving it time our water looks great. Now I have two problems. After shocking the pool in the evening, we are able to maintain a free chlorine reading of about 4 ppm overnight. I go home at lunch and bring some water back to work with me to test, and verify that the free and total chlorine are about 4.1 and 4.5. But, by the time I get home in the evening the chlorine has dropped to nothing. 350-018 We have a chlorinator that we keep tri-chlor tablets in but for some reason it doesn't seem to be working. We even added some tablets to our skimmer basket (this is not our normal practice) just to make sure it wasn't the chlorinator. In past seasons, if we loaded our chlorinator up, even at a low setting, it would over chlorinate the pool big time. So we would always keep about two tablets in and this would last 3 or 4 days, even in hot weather. It's still cool (temp is about 65) so why are the tablets not working? Is it time to load the chlorinator up? 640-721 So every time our chlorine drops to zero, we shock again, and the same thing happens. Our pH is now dropping below acceptable range too. The other question is our stabilizer level. When using the drop turbidity test, results indicate that level is too high and we have been able to get it down to 100, 70-562 with partial water changes. However, if I test with test strips, they indicate that there is no stabilizer. It doesn't change color at all. All other parameters on the test strip are very close to what I get with a kit, or here at work. If there really was not stabilizer, this would explain the chlorine not lasting right? But I thought the drop turbidity test was most accurate. We have a 24' x 52" above ground pool. Thanks.