I have 26 round, above ground, 15000 gallons, 150sq ft cart filter. About 1.5 weeks ago i had some green algae spots. Never green-green water just spots. still gross. i went and got test kit wal-mart vacuumed and brushed pool. After 2 bags hth shock, 4 gallons of bleach and 1.5 box borax(ph was low) the green-spots still came back(not as bad). as of today 7-14-14 ph 7.2 chlorine 9(it was really high 25 for about 3-4 days and no green spots) and cya 55-60. I don't put the cover on at all even if rain is coming cause thats when all this started. How do i get rid of this and prevent it from coming back? also, i live in michigan and have to use well water to add water to the pool. I love my pool and want it to look beautiful. The water looks nice and clear except for these spots once and while. Can you help me???