"Sparkling" Green Pool Water

[Jeff Miami]

18,000 Gallon, Saline Pool, No Heater installed.

Pool Chemistry was WNL with test strips and standard dilution tests. Also supplemented with a CYA melamine visual test which agreed with test strips and indicated CYA < 20 PPM.

Added 4 lbs of Suncoast Stabilzer/Conditioner to pool in the evening. The following morning, pool water had turned light green. No indication of algae in pool or in filter after backwash.

Retested water, and then had sampled checked at pool store. Pool store readings as follows.

TChlorine 5
FChlorine 5
CChlorine 0
pH 8
TAlk 120
Calcium 240
CYA 90
TDA 4600
Copper 0
Salt 3200 (Generator reads 2900)

I've never trusted the pool store, and my strips read T/F Chlorine closer to 4, pH 7.8, CYA 50. A manual melamine test for CYA reads 35-40 PPM.

Any ideas on why this happened? Have searched older posts, and don't believe it is algae, and there is no copper in the water.

Thanks

[chem geek]

I read somewhere recently about a bad batch of CYA that colored the pool water. I can't seem to find this and I don't remember where I read it. Sorry.

[Guest]

There may have been some free copper in the water, but with a FCl level of 4-5, the copper may have oxidized and caused the discoloration.