Green water after clearing the stains

[sandysbiz]

I have recently used Stain Free from Natural Chemistry to clear the iron stains on my skimmers and light/return fixture. The stains did clear, so I added Metal Free maintenance dose (I have already put the initial dose & now maintaining). The water was clear for about 24 hrs, then it turned very cloudy, and I found no FC when I tested. I suppose that algae started when the FC was down to 0 ppm for the Stain Free dosage.
I shocked it to 20 ppm, on Tuesday night, and noticed that the iron stains are back on Thursday morning. I added more of the Metal Free, about 6 to 7 oz, and an hour or so later the water is green.
This moring, Thursday, my readings are:
FC 15.5
CC trace
pH 7.6
T/A 170 ( it does run high)
CYA 40
CH 260

PLEASE advise what I should do. Thank you very much for the help in advance 8)

 

[JasonLion]

You need to be really careful about shocking right after a stain treatment. You should read the Pool School article on metals and the ascorbic acid treatment artile it links to for more details and possible solutions.

 

[frustratedpoolmom]

I was reading Waterbears stain treatment article yesterday and he said be sure to use PolyQuat 60 algaecide to prevent an algae bloom while doing a stain treatment, and not to shock for 2 weeks following the stain treatment. Bring the FC up slowly, using sequesterant to keep the staining from returning.