I checked the pool this morning and it was still green and clear but some cloudiness. We have a 27 foot round, 52 inches deep (16,500 gallons) pool on a sand filter. We use to have an ionizer and catridges but switched to sand filter and chlorine this year but seem to have more troubles getting everything balanced. Hopefully it will get easier. Five days ago we added 5lbs turbo shock and then added Phosfree and waited 48 hours per pool store directions and then vaccumed the pool. They then advised us to add 20 lbs of calcium over the pool three days ago and the water should have been blue but it wasn't. On friday (2 days ago) is when I added the metal, scale, stain control because I had my own theory because it was the only thing I had not done. Whithin an hour the pool was a pretty blue color and clear finally but it only lasted for 24 hours then turned green ago yesterday evening and has stayed this way. I did add 6 ounces of algecide last night but that is everything in the pool at this point.

Current readings:

OTO/Phenol Red Kit: CL/BR 1.5/3.4 PH 7.6 Both show Ideal


6 Way Test Strip:

Hardness 1000
Total Chlorine 0
Free Chlorine 0
PH 7.2
Alkalinity 120
Stabilizer 0

As you said it must be metals (iron) since that was the only thing that allowed the pool to turn blue for a day. I just need to figure out directions on how to get them cleared permanently.