Burn off?

[Earl42]

I left my cover off all day today and burned off 8ppm of FC. Is this normal for a CYA of 70 with 103 degree weather? Also FC dropped from 8 to 0. If I add enough chlorine to get it back to 8, is it safe to swim, or do I have to shock it? CC was maybe .5 (very slightly pink) clear with one drop of R-0871.

Also, pool is not 17K, more like 13K gallons. I will fix my sig when I do some better measurements.

 

[Richard320]

Sounds high to me, with that much CYA. Might be time for an overnight loss test. pool-school/overnight_fc_test

 

[Earl42]

Doing so tonight.

 

[Speedo]

I have a CYA of 95, I'm keeping it around 11 FC, yesterday was full sun all day long and I lost 5 ppm. When covered I average about 1.5 ppm loss per day.

Plus I REALLY need to clean it. I'm assuming my biggest problem is that the past week+ it has been covered most of the time and I don't pay as much attention to leaves and dirt collecting in the center, I'll bet once I clean it my loss will be much less.

 

[Earl42]

Different problem now. I am shocking it. But, every time I add large amounts of chlorine, I get a much higher FC then I should per the pool calculator. I am pretty sure of my 11-12K gallon size. I tried to shock up to 28 and ended up at 40+. I waited 1 hour after putting in the chlorine to test. What else could I be doing wrong?

 

[duraleigh]

What else could I be doing wrong?

Almost always a calculation error. Post your math and there are hundreds of sharp-eyed assistants eagerly waiting to help you find it.

 

[Earl42]

Which calculations?

 

[Bama Rambler]

I think Dave means the pool size calcs.
Are you using 6% bleach?
Also, Are you adding gallons or jugs? i.e. when the PC calls for 5 gallons (3.5 jugs) are you adding 5 jugs?

When I enter 5 jugs instead of 5 gallons in the PC I get that it adds exactly 40 ppm FC.

 

[Earl42]

I am using 96 ounce jugs of 6% bleach. I am pouring in the number of jugs that it calls for. I do have the jug size set to 96 ounces.

to go from 4 to 28 FC in my 11370 Gallon pool, it says to add "4 gallons 2 quarts or 5.9 (96 oz) jugs" so I added 6 jugs at 96 ounces each.

 

[Bama Rambler]

Test the FC then measure and add one gallon of bleach then after 30 minutes test it again. See what one gallon raises it.

 

[shortdogOH]

Is it mixing well in the pool? If you have double-checked all your numbers and tests, I would say trust your pool. I think the pool calc is intended to get you in the ballpark, and each situation might need to be tweaked a bit. Although, 6 jugs to 4 jugs is quite a big tweak.