Yellow/brown stain. what the heck happened?

[pmatt]

Everything was going well. Water was clear. Pool is not covered during the winter. Changed over to SWG in Feb. Water was getting warmer and FC was coming up. A couple of days ago the water seemed a bit cloudy. My CYA was a little low at 30 so I had socks of CYA in the skimmers to bring the level up to 70-80. FC was 2.0 (trying to find the sweet spot on the SWG) and there was no CC. PH 7.5 Water temp is 76

The next day the water was cloudier. FC was 2.5 with a CC now of .5 My CYA was up to 50 I'm thinking is this the start of an algae bloom. I thought the safe thing would be to SLAM. Water temp is 77

I thought the SLAM was working, the water was clearer but I saw the fiberglass steps were starting to get a yellow/brown stain. A CL tab sitting on it for 15 min had no affect. Vitamin C tablet made it instantly disappear in a spot around the tablet. (metal?) In the winter when we bought the house I had tested for iron and copper ... 0 City water is the source.

It seems the high CL from the SLAM caused the reaction. Is that common? SWG is off and SLAMed with 10% Walmart bleach per poolmath with a 30 then 50 CYA

Numbers right now (3 days in)
FC 28
CC .5
CYA 60 (still dissolving some CYA in socks)
CH 80
TA 100
ph 7.2

Any suggestions??

 

[jblizzle]

If you have metal in the water, then the elevated FC level (which raises the pH) can cause the metal staining to occur.

What is worrisome to me right now though is that when the FC > 10ppm, the pH test will read artificially high. If you have a pH reading of 7.2 while the FC is 28ppm, I think you pH might be very very low.

 

[pmatt]

Do you think I should bring the ph up?

 

[jblizzle]

Yes, but hard to say how much since your FC is so high.