A Case of the Pool Measles

[waterbear]

From your description this could be cobalt....only seems to happen to fiberglass pools from what I understand. I will have to do a bit of research and see what I can find out about it. From my understanding oxalic acid is the most effective treatment for this. United chemicals has an oxalic acid product designed for colbat staining in fiberglass pools. Have never used it so I can't tell you how well it works. There is some data that may indicate low calcium levels might be a contributing cause of the cobalt staining but nothing conclusive that I have been able to find.

[Evexon]

From your description this could be cobalt....only seems to happen to fiberglass pools from what I understand.

I believe you are right. It seems to be the only alternative left. I did some poking around on the web and found two products that deal with Cobalt staining; "Cobalt Cure" (United Chemical) and "Jack's Magic". The United Chemical has a better feel to it so I guess I will give it a try. The process is very similair to the advice in the "Brown stains spreading" thread. I wonder what the main ingredient is in Cobalt Cure?

Best,

Steve

[waterbear]

Cobalt cure is oxalic acid. I checked the MSDS. Jack's Magic just says proprietary mixture in the MSDS but the same product is used for iron stains also so I will bet it is also oxalic acid since that also works on iron.