Pool consuming 4 ppm of Chlorine per day. Is this normal?

[Babe the Blue Ox]

23,800 gallon above ground pool. Vinyl liner. Full sun. Crystal clear water. Average recent temps in low to mid 80s. Taylor FAS-DPD test kit.

pH - 7.7
TA - 110
CYA - 50
CC - 0

Taget FC - 6
Min FC - 4

I've been needing to raise the FC each day to 8 in order to keep it from dropping below 4 by the next day. That generally takes one full jug (121 oz) of 8.25% Great Value bleach from Wal-Mart. Some days take more than one jug.

I've performed a couple of overnight tests to verify no chlorine loss at night.

3 bucks per day seems pretty cheap to run a pool, but the Chlorine use seems high compared to other results that I've read in this board.

Is 4 ppm per day normal?

 

[Smykowski]

Re: Pool consuming 4 ppm of Chlorine per day. Is this norma

4ppm seems a bit high, but with full sun and that giant surface area for the sun to attack, probably still within normal. You can try bumping the CYA up to 60 to see if that slows the chlorine consumption. Just watch your min FC like a hawk. If you were to need to shock, it would start getting difficult.

 

[Richard320]

Re: Pool consuming 4 ppm of Chlorine per day. Is this norma

4 ppm could be normal if you live somewhere like Phoenix or Las Vegas and get a lot of intense sun and a lot of swimmers trying to cool off.

The best way to tell if you're developing a problem is the overnight loss test. The chlorine is either being consumed by organics or sunlight. This will rule out sunlight.

 

[woodyp]

Re: Pool consuming 4 ppm of Chlorine per day. Is this norma

Mine eats between 3.5 and 4 daily for the last 4 years. Little less when the water is not as hot, but the pool is full sun---------period! It seems to be...MY....normal at least with my cya around 50.

 

[linen]

Re: Pool consuming 4 ppm of Chlorine per day. Is this norma

Is that usage regardless of swimmers (with and without)?

Do you get a lot of organic debris in the pool?

 

[Babe the Blue Ox]

Re: Pool consuming 4 ppm of Chlorine per day. Is this norma

I should have mentioned that 2-3 swimmers use the pool for a couple of hours 4 or 5 times per week. Usage does not appear to have an effect on chlorine loss.

The only debris in the pool are a few grass clippings if I mow on a windy day.

 

[duraleigh]

Re: Pool consuming 4 ppm of Chlorine per day. Is this norma

Pretty normal. Those swimmers have some effect whether you detect it or not. I lose about 3 ppm daily, Full sun and VERY little bather load except for Molly the Dog.

 

[chem geek]

Re: Pool consuming 4 ppm of Chlorine per day. Is this norma

The chlorine demand from bather load in a residential pool is generally rather low. Every bather-hour is roughly 4 grams of chlorine demand (as ppm Cl₂). So in a 10,000 gallon pool, every bather-hour is only 0.1 ppm FC. It would take 7 bather-hours in a 7500 gallon pool to have 1 ppm FC chlorine demand from those bathers. This assumes, of course, that they aren't urinating in the pool. One cup of urine is roughly the same as 8 bather-hours.