why the jump from FC 4.5 - 7.5?

[9needawin]

Last week my number were:
FC = 4.5
ph = 8
TA = 90
CYA = 40

I made (or tried to make) a few adjustments suggested by Jason over the last week and ended up today with:
FC = 7.5
Ph = 7.5
TA = 70
CYA = 50

I overshot the trying to lower the PH with MA and had to counter with Mule Team 20. My question is why the big jump in FC?
It has been hot and plenty of sunlight. I have not changed my SWG and it is at 60% and runs from 10:15 am to 5:30 pm

Is the time of the day that big of a difference? The second test with the high FC was first thing in the morning in the shade, no
Swimmers, and swg off.

The algae nightmares have me very hesitant to reduce the swg percentage, but it really looks like I need to?? I will also retest CYA later this week and add more to get closer to the pool school recommended level.

Thanks again.

 

[Richard320]

You probably killed off something that was consuming your chlorine. And you added CYA, which saves it from the sun. If it keeps going up, you just need to turn down the SWG a little at a time until you reach the magic number.