Cyanuric acid

[Jsf721]

Can I this be checked at dusk ? I won’t be home before 7 and want to check the cya. Is this accurate in less than bright sun ?

 

[Newdude]

It does best with overhead sun.

 

[DrewLG]

Can I this be checked at dusk ? I won’t be home before 7 and want to check the cya. Is this accurate in less than bright sun ?

If you've driven a car with a dirty windshield, you know that it's a lot harder to see through it in bright sunlight than in other conditions. The CYA test, which relies on the cloudiness of the test sample to obscure the dot, works exactly the same way.

 

[Jsf721]

If you've driven a car with a dirty windshield, you know that it's a lot harder to see through it in bright sunlight than in other conditions. The CYA test, which relies on the cloudiness of the test sample to obscure the dot, works exactly the same way.

Thanks guys. Was able to test Sunday in the Sun and it looks like I’m down about 10 points with a 12” drop and refill. Might be a little more since the pool only mixed 2-3 hours when I tested. Pumped out from the bottom of the deep and filled from top of shallow. Took 45 minutes to drop 6” and 6 hours and then 7 hours to refill. Did that 2x. My guess my sprinklers slowed the over night fill as it took a little longer.