Hello, I'm new to this site and am happy to have found it. We purchased our house 2 years ago with an existing pool and have had trouble from day 1. We are previous pool owners (10 years) and never had problems so this has been frustrating .
We had the same algae problem last summer so after following the recommendations of our local pool store several times with no luck we decided to have the pool drained and acid-washed. Once that was completed I purchased the Taylor K-2006 kit to make sure all chemicals were kept in check. I've noticed the pH goes up quickly on this pool and I'm constantly adding acid to keep it closer to 7.5-7.6. I brush constantly but have been getting the yellow spots in the deep end on the wall and steps. I tried raising the FC to keep it near 5 in order to try and control the yellow algae but every day I go out and see new spots. I use a floater for the chlorine tabs and keep it wide open and I've also added dichlor to raise the FC. I added 8 oz of Yellow Out several days ago and then raised the chlorine again. After reading a bunch of posts I'm guessing you're all cringing with the mention of the yellow out and tabs! The water is pretty clear and I wouldn't describe it as cloudy. There is very little debris that gets into the pool and I cleaned the filters on May 5th.
The pool is approximately 20K gallons, in-ground plaster, with a new Pentair Intelliflo VS 3hp pump running 8 hours (4 hrs @ 2800 rpm and 4 hrs @ 1500 rpm). There is a waterfall feature, Hayward sweeper and Hayward SwimClear Cartridge Filter.
20K gallon in-ground plaster, Pentair Intelliflo VS 3hp pump, Hayward Sweeper and Swimclear Cartridge Filter, waterfall feature