Overnight Chlorine Test more than 1PPM

[rich6429]

Hi - this all started with me "thinking" that my pool is slightly cloudy. But this could also be me trying to be too perfect and precise when it comes to the pool. I test almost daily (or every 2 days). I dont always log the results in the PoolMath app. But in most cases, my FC is in the 5ppm, PH (7.5-7.8), Alk is steady between 80-90 and Hardness never moves from 130. CYA is 60 and has been steady. I run my pump for 24 hrs (1800rpm) and sometimes would run for 2 hrs at (2400rpm). The total movement in water does cover more than 3 times the total water capacity of the pool.

So again, I feel like the pool is slightly cloudy, although others feel it looks fine. I know want to use a pool clarifier since there may be a reason for the cloudiness. I have done 2 things...
I ran my pump for a good 6 hours on high (2900rpm) and seems to be more clear than prior. I also did an Overnight Chlorine test...and low and behold, I lost 1.4PPM overnight (12 hours).

I guess I have 2 questions...
Is this just due to poor circulation and I need to run my pump on higher RPMS more than just running long with low RPM?
Or do I need to shock (assuming algae problem) since the overnight chlorine loss test showed I lost 1.4 ppm

I used a taylor kit and tested with 25ml, so I can measure with 0.2ppm per drop.

 

[Texas Splash]

The speed of the pump has no bearing. The loss of FC overnight, if it was dark during the entire 12 hrs you noted, is from excessive organics and thus a SLAM Process is warranted. If the sun hit the water at all during your OCLT, then I would consider doing a 2nd OCLT only during hours of darkness. 6-8 hours is enough test time. I would also stick to the basic 10 ML water sample size with ONE generous scoop of powder, and the number of drops is divided in half. No need to use extremely precise 25ML/0.2 method.

 

[Jimrahbe]

Rich,

If you lost 1.4 ppm overnight, then it is algae. That assumes that you did not make a testing error.

Test after the sun goes down, and again before the sun comes up. In theory, the two tests should be the about same, unless you have algae.

I assume you had the SWCG off when doing the OCLT.

If your pool is clear, it should not take long to do a SLAM.

Thanks,

Jim R.

 

[tim5055]

As has been pointed out - 1.4 loss on a properly conducted OCLT means algae.

A one time "shock" is not the way to go. We follow the SLAM procedure to the end

SLAM - Shock Level and Maintain

We’ve all had to deal with a green pool. Clear algae from your pool with a SLAM! Read here to use shock level and maintain to clear your pool.

www.troublefreepool.com

 

[rich6429]

Rich,

If you lost 1.4 ppm overnight, then it is algae. That assumes that you did not make a testing error.

Test after the sun goes down, and again before the sun comes up. In theory, the two tests should be the about same, unless you have algae.

I assume you had the SWCG off when doing the OCLT.

If your pool is clear, it should not take long to do a SLAM.

Thanks,

Jim R.

thanks...and yes, SWCG was off during OCLT.

 

[rich6429]

The speed of the pump has no bearing. The loss of FC overnight, if it was dark during the entire 12 hrs you noted, is from excessive organics and thus a SLAM Process is warranted. If the sun hit the water at all during your OCLT, then I would consider doing a 2nd OCLT only during hours of darkness. 6-8 hours is enough test time. I would also stick to the basic 10 ML water sample size with ONE generous scoop of powder, and the number of drops is divided in half. No need to use extremely precise 25ML/0.2 method.

so 2 things...I didnt exactly do it while it was dark...but definitely sunset and perhaps 1 hr away from complete darkness and its been bright for 1-2 hours in the morning (but I wont exactly say sun was out)...was actually overcast. You think that may have had an impact?

secondly...never heard of using the 10ml water sample size as a precise way to measure (always done 10ml and counted 0.5ppm). To clarify, do I put 1 scoop? And divide the number of drops in half?

 

[Texas Splash]

so 2 things...I didnt exactly do it while it was dark...but definitely sunset and perhaps 1 hr away from complete darkness and its been bright for 1-2 hours in the morning (but I wont exactly say sun was out)...was actually overcast. You think that may have had an impact?

You might get away with soft light starting to peek-over the horizon, but once the pool is exposed to any sunlight you can lose FC.

never heard of using the 10ml water sample size as a precise way to measure (always done 10ml and counted 0.5ppm). To clarify, do I put 1 scoop? And divide the number of drops in half?

The most popular TFP FC testing method and can save you some reagent. 10 ml water sample size with ONE generous/heaping scoop of powder. Mix and add drops until clear and divide the answer in half. Example: 20 drops equals an FC of 10. Accurate and reliable.

 

[rich6429]

You might get away with soft light starting to peek-over the horizon, but once the pool is exposed to any sunlight you can lose FC.

May try again (in the dark) just to be sure...will rain affect the result?

 

[Texas Splash]

will rain affect the result?

Not as long as the pump is on to mix the pool water continuously.