My pool also has had recurrent mustard algae problems despite high chlorine levels. I've kept it in check with slightly elevated FC and regular use of my robotic cleaner. Last year the robot failed and I went with brush and vacuum. The Yellow Beast started appearing in corners, liner seams and depressions in the floor. Several weeks of ++SHOCK++ levels and daily brushing didn't eradicate it.

My pool has solar panel heat and I use a solar blanket to retain heat. These may contribute to my difficulty removing the Mustard Algae.

I'd like to join this phosphate removal study this summer as well (now the pool is ice) - if I may.

Should I start a new thread or keep this all together here.