Excessive FC loss? Or something sinister.

[tadcpht]

This morning (715am)
FC 15.5
CC 0.5
Cya 40
pH 7.5
Alk 110
This afternoon (4pm)
FC 8
CC 0.5
Cya pH alk same.
My pool gets sun almost the whole day.
Is this normal FC loss for a day with my cya or could something nasty be in the water? I am planning on an OCLT soon (prob Tuesday). I'm am almost out of R-0871 solution which is why I haven't started the process yet. Thanks for any replies.

 

[AimeeH]

Wellllllll, do you suspect something sinister since you had your chlorine at 15.5 with a CYA of 40? That is shock level not maintenance level. So with that.....I'd suspect something sinister.

 

[tadcpht]

The last few days we have had heavy bather loads and seemed like my FC would drop more than it should. So I brought up to shock level and wanted to see how much I lose in a typical day. Just seems like a lot

 

[AimeeH]

How does the water look?

Do the OCLT for sure. And if that good then you might want to increase the CYA.

 

[tadcpht]

Water looks good. Deep end just a touch hazy.

 

[AimeeH]

OCLT in order but hazy water at high CL consumption= SLAM.