This is my 4th season with a 30 foot above ground pool We use a cartridge filter system. I need some advice on yellow algae. Little background, I had no problems with the pool until we opened it in 2015. It was a green from a bad cover, so debris got in it.
We cleaned it up without any issues, or so we thought. By the end of 2015, we noticed what looked like brown yellowish spots that dissolve when touched. We think the shock we used to clean up the original outbreak led to very high cya levels. We used tri-clor shock and tabs as suggested by my pool retailer. We believed that the chlorine wasn't working.
This year, we opened the pool a month ago with a few spots but in recent days the yellow/brown spots have exploded. The water is clear and the spots are only on the floor. Pollen is high but I am not seeing it on my deck or furniture.
This year I changed out the cartridge filter, switched to a Pool RX, system and switched to a calcium-hypo chlorine. We treated with Yellow Clear and liquid chlorine and it didn't work. Alkalinity was ok, PH was a 7.4 but we also learned that our CYA was through the roof ...150. We stopped treatments and we drained and filled several times and we are now down to a 75-80 range. I added 12 pounds of shock.
We have been testing with on of the Taylor system that uses the drops. We've also started using pool perfect. Ive vacuumed to waste twice, vacuumed though my filter, and brushed several times. Still no luck.
Any ideas or help would be welcomed. Thanks in advance.