Our pool is a 15 year old people tech pool. 3 years ago we started battling green algae. Our pool has always been with a paid service but the quit. We got a new service, dumped water (1-1/2 year ago), replaced sand in sand filter, then they quit after throwing a lot of extra money in. New guy took over, it’s GREEN!! We’ve done algicides, always checking PH, tons of chlorine, TRIED EVERYTHING. New pool guy already frustrated at me for telling him it’s green. I pay $120 a month. And this is the first full week it’s been hot outside for swimming..