FC dropped from 4 to Zero in four days

[Mark IT]

Hi I have been using a winter cover on my pool. At first, my pool showed little or no change in the chemical makeup. This weekend I tested my pools and was shocked by the drop in Chlorine. The water showed almost zero evaporation. but the CHL dropped to almost zero. I like using the pool cover because - it keeps the pool clean of debris, reduces evaporation by 90%, keeps the pool water warmer, and should reduce the chemical cost. Not sure what happened to drop the chlorine so fast though.

	5/8/22	5/4/22	5/1/22	4/29/22
FCL	0.16	3.98	5.33	7.5
TCL	0.45	4.02	5.34	7.5
PH	7.2	7.5	7.4	7.5
ALK	37	52	49	55
CHD	230	234	237	219
CYA	66	66	66	72

 

[YippeeSkippy]

Mark, please refer to chlorine as FC or CC, as our abbreviation for Calcium Hardness is CH. Thanks.

FC is a *consumable* product in your pool. Sun, bathing load, algae... all those things eat up your FC. That's why it has to be replaced daily.

Are you running your SWG at high enough percentage and for long enough? Is it properly sized for your pool??

You folks in TX are getting a lot of heat right now... sun too? That daily "sun tax" for uncovered pools is up to 4ppm / day.

Maddie

 

[atxjmy512]

Mark, please refer to chlorine as FC or CC, as our abbreviation for Calcium Hardness is CH. Thanks.

FC is a *consumable* product in your pool. Sun, bathing load, algae... all those things eat up your FC. That's why it has to be replaced daily.

Are you running your SWG at high enough percentage and for long enough? Is it properly sized for your pool??

You folks in TX are getting a lot of heat right now... sun too? That daily "sun tax" for uncovered pools is up to 4ppm / day.

Maddie

I'm in Texas... My pool gets a lot of direct sun. I usually lose at least 2, sometimes 3 ppm per day during cloud free days.

 

[YippeeSkippy]

Yup.... that is why I said "up to 4"

 

[Minda Martin]

Mark, please refer to chlorine as FC or CC, as our abbreviation for Calcium Hardness is CH. Thanks.

FC is a *consumable* product in your pool. Sun, bathing load, algae... all those things eat up your FC. That's why it has to be replaced daily.

Are you running your SWG at high enough percentage and for long enough? Is it properly sized for your pool??

You folks in TX are getting a lot of heat right now... sun too? That daily "sun tax" for uncovered pools is up to 4ppm / day.

Maddie

Math is not my strong suit. If a pool loses 4ppm's a day, can you convert that to inches? My pool on a hot summer day can lose 1/2 inch a day. Is that not normal?

 

[Wobblerlorri]

Math is not my strong suit. If a pool loses 4ppm's a day, can you convert that to inches? My pool on a hot summer day can lose 1/2 inch a day. Is that not normal?

You're seeing evaporation. FC is measured in parts per million, and is how much free chlorine is in your water. Evaporation has no effect on FC besides concentrating it, unless something else is eating it up (sun, bather load, etc).

 

[Minda Martin]

You're seeing evaporation. FC is measured in parts per million, and is how much free chlorine is in your water. Evaporation has no effect on FC besides concentrating it, unless something else is eating it up (sun, bather load, etc).

Oh! Ok! I see I'm comparing apples to oranges. It just seems that 1/2 inch evaporation per day is a lot, which is a whole other subject! Thank you for your response!

 

[YippeeSkippy]

I lose more to evaporation during hot/dry weather. Indian Summers I lose the most.

 

[Minda Martin]

I lose more to evaporation during hot/dry weather. Indian Summers I lose the most.

Thank you! It seems I'm losing too much water. I had planned to do the bucket tests this season to see if I have a leak. I run my pump pretty much 24/7. I always open to algae and have to slam but once I get it going I tend to keep a good chemical balance until closing.