Daytime Chlorine Loss Test

Homebrewale

Well-known member
Apr 21, 2020
331
Apex, NC
Anyone not new to this site knows about the OCLT. Is there a similar daytime version? I ran the OCLT so I know my FC loss overnight. Now if I pick a typical summer day, could I test the FC at dawn and sunset without the SWG running to find the FC loss during the day? From there, use this information with PoolMath to find an initial setting for my SWG. After that, it's a matter of tweaking the SWG to get to where the FC generation is equivalent to the FC loss.
 

Msch99

Gold Supporter
Bronze Supporter
Jun 11, 2018
908
Verona, MO
Wouldn’t it be about the same amount of testing if you set swg for 4ppm per day, which should be high, and test at same time each day?
Maybe better than no chlorine generation for few days.
So many variables to consumption. UV, swimmers etc
 

Homebrewale

Well-known member
Apr 21, 2020
331
Apex, NC
Wouldn’t it be about the same amount of testing if you set swg for 4ppm per day, which should be high, and test at same time each day?
Maybe better than no chlorine generation for few days.
So many variables to consumption. UV, swimmers etc
Sometimes I feel like the Price is Right game where you guess a price and they say higher or lower.

Also I'm thinking that if I know the FC loss during the day and I have a few straight days of similar weather, I can check to see if my SWG is operating at specs. My pool is used exactly the same from Monday through Friday so number of swimmers is not a variable. All equipment is on a program so my only variable is weather (sun, clouds, rain).
 
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mgtfp

Bronze Supporter
Mar 5, 2020
598
Melbourne, Australia
Pool Size
66000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Astral VX 7T
Just remember that when you do this, you will be taking a risk that your chlorine can drop below the min level, which could trigger an algae problem. So, you should be high enough in chlorine before you start that test. But if you have to get your chlorine level higher than normal for that test to reduce the risk of slipping below min, you will have higher absolute chlorine loss (the UV loss is more or less a certain percentage of your chlorine level).

I would go with @Msch99 's suggestion: Have your SWG generating a constant amount of chlorine through the whole test period. Any chlorine losses or increases measured you can than use (with the help of PoolMath) to fine tune your SWG settings.
 

Bvacchiano

Silver Supporter
Apr 6, 2018
287
Sugar Land, Texas
Get your FC to something higher than the recommended the night before. Wake up turn your SWG off take another reading. Leave SWG off all day. Take reading at end of day. You should now know your daily FC demand. I do this on a sunny day.
 

Newdude

Well-known member
Jun 16, 2019
4,846
NY
Sometimes I feel like the Price is Right game where you guess a price and they say higher or lower.
Its EXACTLY like Price is Right but backwards !!! In our version you automatically lose if you guess under. Always guess higher and it will be smooth sailing.

For example, with your 60 CYA, your minimum is 3 and your target is 4. I keep mine where I can lose the standard up to 4PPM per day and still be at target. If if maintains 8 all week, no harm done whatsoever.
 
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