For the past few weeks I can't get rid of the algee. I have put almost 2 gallons of algeeside in the water and 10
Lbs of shock. I would wait the said amount of time and vacuum to waste. I back wash every few days. The other day the lady at the pool place said not to do that cause it is just wasting out all my chemicals. My ph and ta are almost non existent. I have put in 5 plus lbs of borax and baking soda. I have an In ground vinyl pool 25,000 gallons and a Sand filter. What I am doing wrong?