Dropping 4-5 FC a day

[merc123]

I’ve seen it on various pool websites. I did see a 1.5 PPM of FC Also.

Right now I’m consistently at 40 ounces every night after the sun goes down. It ends up at between 3-4 FC at the end of the day. Doesn’t matter if anyone swims or not.

 

[kellyfair]

Check your CYA one more time... you are adding to first line, glancing, still see dot? Add to second line, glancing, and so on?

 

[kellyfair]

Are you sure about your volume? Mine is 6000 gallons...

 

[kellyfair]

For a 7600 gallon pool, with CYA 50, it would take 39 ounces of chlorine to go from 3 FC to 7 FC.

To slow down chlorine loss you could bump CYA but I would first make sure of the current number, doing test as above in full sunlight, sun behind you.

 

[JW1]

For a 7600 gallon pool, with CYA 50, it would take 39 ounces of chlorine to go from 3 FC to 7 FC.

To slow down chlorine loss you could bump CYA but I would first make sure of the current number, doing test as above in full sunlight, sun behind you.

Is that correct? I’m getting 31 ounces unless I’m inputting incorrectly.

 

[kellyfair]

You are using 12.5% bleach? I used 10%. I’ll go back and check post, I may have read OP’s bleach strength wrong.

 

[JW1]

You are using 12.5% bleach? I used 10%. I’ll go back and check post, I may have read OP’s bleach strength wrong.

I’m using 12.5.... that is the difference. I started wondering if I was using pool math Incorrectly.

 

[kellyfair]

OP is using 10%.

 

[kellyfair]

I really feel your water volume is higher than you thought, and your CYA may be lower than you thought.

 

[merc123]

Doing the CYA test in sunlight and not in the kitchen I'm at just a little under 50. I'm at 2.5 FC right now. According to the app to get 7 FC I need to add 37 ounces. 40 ounces would be 7.3.

I have double checked my pool volume by measuring the height of the water itself and still around 6500 gallons.

 

[Oly]

I know you said that your overnight FC loss is minimal but I have to ask, do you have a ladder in your pool?
The pool ladder I used when I had an AGP was designed to allow water inside and was an algae breeding ground.
Just a thought.

 

[merc123]

I know you said that your overnight FC loss is minimal but I have to ask, do you have a ladder in your pool?
The pool ladder I used when I had an AGP was designed to allow water inside and was an algae breeding ground.
Just a thought.

We take it out nightly for safety.

 

[Oly]

If it is hollow then check the insides closely, it may be the source of your FC loss and pulling it out at night would explain the low overnight FC loss.

 

[merc123]

If it is hollow then check the insides closely, it may be the source of your FC loss and pulling it out at night would explain the low overnight FC loss.

That is a possibility. I thought of that after I typed we pull it out at night. It definitely lets water into it.

 

[Rattus Suffocatus]

If you cover the pool when not in use it'll drop to about 2-3 PPM/day FC loss. But 4-5 uncovered in the mid 80's is completely normal. As much as I hate the cover that is why I do it. That and minimizing evaporation which here in the dry desert cools the water down quite a bit and then it's refilled with higher TA water, CH rises... etc... everything in a pool is a tradeoff....

 

[merc123]

I added 40 ounces at 12:21. I just checked FC at 12:50 and it's at 9.5 from 2.5. Based on that kind of math my pool would be 4500 gallons which is quite a difference.

 

[merc123]

If you cover the pool when not in use it'll drop to about 2-3 PPM/day FC loss. But 4-5 uncovered in the mid 80's is completely normal. As much as I hate the cover that is why I do it. That and minimizing evaporation which here in the dry desert cools the water down quite a bit and then it's refilled with higher TA water, CH rises... etc... everything in a pool is a tradeoff....

That makes sense. I just wanted to make sure I wasn't doing something ridiculous.

 

[kellyfair]

I added 40 ounces at 12:21. I just checked FC at 12:50 and it's at 9.5 from 2.5. Based on that kind of math my pool would be 4500 gallons which is quite a difference.

Something is definitely out of whack. Still using 10%?

 

[merc123]

I was. We went on vacation so I threw in the duck with 3-pucks of 4-in-1 and put a cover on. When we got back (10 days later) it was at 26. Uncovered it and vacuumed. Next day it was down to 12.5 and 7 the next day. I removed the ducky so it would naturally drop. I did drill drain holes in my ladder and I think that’s a source of the usage. It had some nastiness in the ladder. So we’ll definitely remove it unless we are in the pool.

 

[merc123]

So since using the HTH 3” tabs in the floating ducky I’ve had a consistent 5-6 FC levels. I’m going to watch CYA but this may be a better solution for me than liquid chlorine. I can dump water to lower CYA and water isn’t costly to refill.