I have a 35,000 gal gunnite pool and upon opening the pool, the water was really green. After a week or so of trying to clear it up, my pump died and also realized that my filter was pushing DE into my pool through the return lines. I decided to replace all of my equipment 2 weeks ago and bought a new 2HP Super Pump, a Hayward DE6020 Pro-Grid 60-Square-Foot Vertical D.E. Filter and a new multiport valve. Once all new equipment was installed, the water cleared up in about a day but I quickly realized I had a 1/4 inch layer of DE powder covering the entire pool floor. I manually vacuumed to waste to remove DE and noticed pool floor was REALLY green. I proceeded over the next few days to brush ( I use a metal brush)the pool everyday to remove the algae but there are now very large areas of green that will not come off (see video) https://www.youtube.com/watch?v=bKtjLb7jQqA
I have shocked the pool numerous times and have also used a Anthony Slyvan Green algecide remover, but it does not remove the green staining.