Green stains on bottom of gunnite pool....


New member
May 20, 2012
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)

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.


LifeTime Supporter
Platinum Supporter
TFP Expert
May 7, 2007
Silver Spring, MD
Welcome to TFP!

I suggest getting a sock, putting some dry acid in the sock, and placing it on a stained area for a couple of minutes. You can also try placing a trichlor tablet on a stain for a couple of minutes. If the trichlor works better then they are organic stains. If the dry acid works better then they are copper stains. If neither works well we need to investigate other possibilities.