I am new to this forum but have been following different threads since mid-August. I have maintained my pool for over 25 years with a yearly persistent issue that I'll describe in a second. Bottomline is that we went on vacation for 11 days, left instructions with my neighbor, and when we came home my pool was emerald green. I guess he went on vacation too! Followed the advice at the pool store and, other than spending a ton of money, got nowhere the first week. When I found this forum, I learned about the relationship of CYA to chlorine effectiveness. Went back to the pool store to ask them about CYA level and was told my level was north of 100. Come to learn that, since all I ever used for years were 3" tablets, my CYA level built up every year. As I keep my pool open over the winter, the winter rains would dilute the CYA so my standard tablet routine worked well early in the swimming season, but I always struggled with cloudiness and algae around mid-August. This year got real bad due to lack of attention when the temps were hovering around 95 degrees and my pool temp was pushing 90.
Bought a T100 kit, started doing it myself and got everything under control to the point my water was blue but not 100% clear. Still slightly hazy to cloudy! Hence the reason I am commenting on this thread.
Tried re-SLAMming the pool for a couple of days with no results (I had already drained half the pool so my CYA was down to 60 and began using 8.25% concentrated bleach). I saw that I might possibly have a filter issue, so, since I could not remember the last time I replaced the sand, I thought I would try that rather than doing a deep cleaning. Found the specs for my sand filter, bought 150 lbs of sand, kept SLAMming for another two days and still no change.
Then, it was either this thread or another similar one, that I saw to clean the ladder. I have a plastic ladder that fills with pool water so rather than cleaning it, and since it is already mid-October, I pulled the ladder out. OMG! The stinkiest, ugliest, greenest swamp water came poring out of the ladder when I tipped it on its side. That's where the algae was still coming from and I think was keeping my pool water from ever really getting clear and deposting algae to the bottom of the pool most every day.
Back to SLAMming for two days and voila, blue, clear and sparkling water the likes of which I have not seen in my pool for a long time!
So, thank you every one that has contributed to this forum for helping ME take control (rather than the pool store) and for teaching me about water and how to maintain it even though I thought I knew what I was doing for the last 25 years. I found the "hidden algae in the ladder trick" in a thread when I came onto here and searched for "still cloudy". I still have a LOT to learn but I am looking forward to next season, being in control, and spending a LOT LESS on chemicals!