Issue with chlorine production

[Tommygarry1]

Good morning TFP community. I am posting this question for a friend of mine who's having a lot of challenges with his Hayward 900, with a T cell Hayward 940. He keeps losing all of his chlorine throughout the day. He does get sun from set up to sundown. I explained to him that sometimes you have to have a CYA as high as 90. Right now his CYA is sitting around 70. I had him test his chlorine at night and then run the cell all night to see if chlorine production would increase. The chlorine level did rise from 1 to 4.5 over the evening. Outside of increasing CYA to 90, are there any other suggestions? I was even telling him to consider switching to chlorine tabs at this point. He's also considering running his pump at night instead of the daytime, but I didn't think that was a good idea either. Any suggestions would be appreciated. Thanks.

 

[ajw22]

Did your friends pool pass the Overnight Chlorine Loss Test?

Have your friend join so he can answer questions directly.

How many gallons in the pool?

What % is the SWG set to?

What is the pump daily runtime?

 

[Tommygarry1]

Thank you for the quick response. My friend barely uses the internet, so getting him to join this would be impossible. He will do that test tonight. To give you more context, he has had a lot of issues with his pool this year. He has stubborn stains that won't go away and was being suggested to use magicJack to remove stubborn stains that he has in his pool. He has so much chlorine lost during the day that he will have a hard time even having a level of three PPM by the time the pool shuts down. So I advise that he adds some supplemental chlorine later in the day when the sun is very weak and then testing it a couple hours later when the sun is fully down. He is going to fully circulate. Keep the chlorinator off and run his pool robot just to keep everything circulating to get a true reading.

 

[ajw22]

Running a T-15 cell for 100% for 12 hours/day in 24,000 gallons will generate 3.5ppm of FC.

That says his chlorine production is normal with an overnight rise from 1 to 4.5.

From what you reported nothing is wrong with his SWG.

Algae is the likely suspect.

Does he have a recommended test kit?

 

[Mdragger88]

For The
Overnight Chlorine Loss Test you want the pump running for at least 30 minutes before each test. It’s often just easier to keep it running.
Swg off.
Fc at target levels for cya
FC/CYA Levels

Does said friend have a single speed pump?

 

[Newdude]

That says his chlorine production is normal with an overnight rise from 1 to 4.5.

From what you reported nothing is wrong with his SWG.

Algae is the likely suspect.

Algae would have consumed some of the 3.5 FC produced overnight, to only see 1 or 2 in the morning IMO.

I think it's simply a target that's way too low, and if it fluctuated from 5 to 8.5, everything would be great.

But since it's danced minimum so often, the OCLT is a given.

 

[Tommygarry1]

Running a T-15 cell for 100% for 12 hours/day in 24,000 gallons will generate 3.5ppm of FC.

That says his chlorine production is normal with an overnight rise from 1 to 4.5.

From what you reported nothing is wrong with his SWG.

Algae is the likely suspect.

Does he have a recommended test kit?

Thank you -- Yes -- I got him the Taylor Kit. He DOES have black algea that wont scrub off and organic stains throughout the pool that will not lighen up. Vitamin C test was negative/ We also SLAMMed his pool once and the stains did not go away (they lightened a little). He will do overnight test. I will report back.

 

[Tommygarry1]

Algae would have consumed some of the 3.5 FC produced overnight, to only see 1 or 2 in the morning IMO.

I think it's simply a target that's way too low, and if it fluctuated from 5 to 8.5, everything would be great.

But since it's danced minimum so often, the OCLT is a given.

One more thing to consider -- Black algea and organic stains encased in calcium are in his pool. The pool was NOT started properly after new plaster work was completed. Pool has gone from cool blue to almost white. Tile was also improper;yinstalled. As a result, he is going to re-do the tile and replace the coping and at that time do an ACID wash and polish. Contractor is guaranteeing color will be restored and stains removed. 2 questions -- Will that work on the stains? and Any concerns of agea and stains coming back post completion assuming water is balanced and chlorine is sufficient?

 

[Newdude]

Will that work on the stains?

It depends on how deep the stains are. Acid washing removes plaster / finish. Sometimes only a little needs removing, sometimes too much needs removing.

Then some contractors get it wrong either way.

No two acid washes are the same.

Any concerns of algea and stains coming back post completion assuming water is balanced and chlorine is sufficient?

If chlorine is kept free and clear above minimum at all times, your friend has his best chances going forward.

 

[Tommygarry1]

Update for you all. He did the overnight test and the pool passed. He is now going to focus on keeping his chlorine levels higher. If they continue to drop, he will add more CYA. Thank you!

 

[Mdragger88]