Can't raise my chlorine level after draining pool

[cmenick]

Please help... 13,000 gallon inground pool. Have ozonator and use Trichlor tabs. My CYA level was 175 and drained 75% of my pool water on March 21. Retested my CYA after refilling and it was 20ppm. Chlorinator set on 2, and can't get FC level over .5ppm. Have been using liquid bleach to support the chlorine level..Water is crystal clear and no signs of algae.

Thank you for your help.

 

[JVTrain]

If you could post full test results along with dosages that you've used, that would be helpful. Are you using Pool Math to calculate your bleach additions? What FC level are you targeting?

You should be dosing to get to 4-5 ppm FC. Do so and test the water for FC and CC 30 minutes after adding. Are you hitting your FC target? Do you have CC above 0.5?

 

[YippeeSkippy]

Which test kit are you using?

 

[cmenick]

Hello,
thanks so much for responding...Attached are my readings from before I drained the pool to current. I have been using a Taylor K-2006 test kit.
Also we have an ozonator and light usage on our pool...So last summer we kept the FC to approx 2 with no issues. We use Pool Math to adjust our chemicals.
Problem is that we have been adding liquid bleach to supplement the chlorine and kept moving the setting up on the trichlor, now up to 4...We have also
kept the chlorinator full with tablets. Our only thought is that the CYA is now so low that the pool won't hold the chlorine.

Thanks in advance for your help,
Cindy MenickView attachment 48045
- - - Updated - - -

 

[frustratedpoolmom]

I guess I have two questions before I can advise...

Have you done an OCLT at all?
What is your plan for daily chlorination going forward?

 

[cmenick]

No I havent done an OCLT...Didn't even hear of this, thanks for bringing this up...But looked up on Trouble Free Pool , it states that I must have at least 3ppm of FC..We never
have our FC over 2, so not sure this will work. The water is crystal clear and we haven't been swimming yet. Completely refilled 77% of our pool on 3/13.

Going forward we are want to use the trichlor tabs and ozonator as we did last summer. This is the second summer owning the pool. Only using the liquid bleach for now.
Thanks

 

[frustratedpoolmom]

Ok well if you are going to use tabs you want to start with a low CYA anyway. Going up to 3 temporarily will not hurt anything, you can do it with 2 even.

The point is to detect any FC loss taking the sun out of the equation. So tonight test the FC and if it drops by more than 1, then something organic in your water is consuming it. I recommend you add 2ppm of liquid chlorine about 5 or 6 pm. Test the FC about 8pm. Compare the results to the test in the morning and see what ya got.

 

[cmenick]

Thanks, will do that...I am a former Chicagoan , been in Texas 3 years, miss Chicago food.