Confusing Pool Series of Events

mikesnead

Well-known member
Jun 15, 2017
58
Winter Park, FL
Here’s where I stand at 9:20am:

FC 4.5
CC 0.5
pH 7.2
CYA 80 (d’oh)
Salt 4200
TA 60
CH 450

Cell back on to 100% 24/7.
Water still wonderfully clear to my eye.

Off to buy big ole pile of bleach.
 

Derb22

Gold Supporter
Apr 29, 2018
299
Roswell GA
Mike,
while not impossible you are now going to have to SLAM at a level of 31 and hold it with that CYA amount. That’s going to take a ton of bleach. Make sure your CYA test is correct. I can’t imagine how or why you lost the CYA in the first place. It doesn’t go anywhere except from splash out.
 

mikesnead

Well-known member
Jun 15, 2017
58
Winter Park, FL
Mike,
while not impossible you are now going to have to SLAM at a level of 31 and hold it with that CYA amount. That’s going to take a ton of bleach. Make sure your CYA test is correct. I can’t imagine how or why you lost the CYA in the first place. It doesn’t go anywhere except from splash out.
Yep ��. I added to get to 80 after my I initial tests yesterday; before I thought I’d be slamming. Luckily my pool is relatively small and, based on my pool clarity, I should have a relatively short slam as well.

The dropping CYA is my big mystery. I expect to lose a bit during summer rains from overflow, but 50ppm drops can’t come from that. Perhaps I have acquired the CYA eating bacteria that chemgeek encountered...
 

mikesnead

Well-known member
Jun 15, 2017
58
Winter Park, FL
Purchased 18 gallons of 10% w/ a very recent date code. 3 gallons poured in which should get me over the shock level, but will test in about 20 mins to allow circulation (pump running on full for that period) to see where I'm at. I'll turn the cell back off after that next measurement. I'll try to test every 2 to 4 hours to maintain.
 

mikesnead

Well-known member
Jun 15, 2017
58
Winter Park, FL
First Test after the initial 3 gallons. Overshot by a bit. Was aiming for 35 (nice number above the 31 shock level for 80 CYA), but hit 47.5!

FC 47.5
CC 0.0

Next test in about an hour as we are leaving for an event right around then. Cell is now off as well.
 

Derb22

Gold Supporter
Apr 29, 2018
299
Roswell GA
Well that should have SLAMMED any and everything. Will be interested in the number after an hour. What’s the weather today? Oh. Never mind it’s Florida. Sunny, hot and going to rain this afternoon. Lol.
 

mikesnead

Well-known member
Jun 15, 2017
58
Winter Park, FL
As of about 6:15 was down to:

FC 35
CC 0.5

Added another gallon ahead of OCLT measurement that will be done in about 2 hrs. I wanted to be sure I’d keep above 31 over night.
 

mikesnead

Well-known member
Jun 15, 2017
58
Winter Park, FL
Passing a Overnight Chlorine Loss Test at very elevated FC levels is typically quite difficult. The error of the test is 10% when FC is over 10 ppm.

Once your pool is crystal clear with no CC, you will most likely need to let your FC drop to the teens before doing a Overnight Chlorine Loss Test.
Pool is crystal clear and the CC test often comes up clear or only very slight pink tint. I’ll let it drift as you suggest into the teens. Thanks for the help!
 

mikesnead

Well-known member
Jun 15, 2017
58
Winter Park, FL
Tested 4:30PM Friday at FC 16 CC <0.5

Tested 10:30AM Saturday at FC 15 CC 0.0

No chlorine additions during this time period, so I did technically pass OCLT even with 3 hrs of sunlight still on the pool :p