Please help get water clear; question about OCLT

[Rita Fosterling]

Hi all,
I am really puzzled and would so appreciate your wise insight and suggestions, everyone! My pool water has been pretty clear since opening about 3 weeks ago, but it isn't now. The pool is consuming more chlorine and looking worse. Today the water was really cloudy! I could make out the drain in the deep end, but NOT clearly.
Here are today's readings:
CYA 40
FC 6 (started at 9)
CC 0
TA 290
Ph 7.6
CH 175
QUESTION: I did the OCLT and lost about 3ppm overnight. However, this test was done after another day of heavy swimming (8 swimmers 8 years old and younger!) So my question is this: Is it reasonable to see a 3ppm drop in chlorine level (during the daytime)l after the pool gets some big-time use like this?? I understand that a drop in chlorine level greater than 1ppm overnight indicates that some organic matter is present and the pool requires a SLAM. But could it also mean that the FC is doing it's job???
QUESTION: Based on this info, does it look like I need to increase FC to 16ppm now? How long do I need to hold it there to make sure I have killed everything bad? Thanks for the help.

 

[Rita Fosterling]

23,000 gallon IG; Vinyl liner; Liquid Chlorine; Purex Triton Meteor 26" sand filter; 1.5 HP Pentair Pump; Well water Taylor TF-;

 

[jblizzle]

So it is cloudy and you failed the OCLT....i think you know you need to follow the SLAM Process process.

If it was just sudden, then likely just due to heavy use, but it sounds like the water had been deteriorating if I understand you correctly.