Chlorine issues

[Apas]

Would love some help figuring out why I can’t get my pool chlorine above 2.0 ppm with tablets. Normally, I use 3 tablets and I am good to go with my chlorinator set to level 2. I’ve increased it to level 6 -still holding at 2.0. The only way to get it above that is by adding shock. I’ve double shocked, once it drops back after the shock—holding steady at 2.0. I know my cya is a tad high, but normally, that doesn’t change my ability to chlorinate.
Chlorine 2
Cya 100
Calcium 350
Ph 7.6
Alkaline 100
I was planning to hold off on draining since the swim season is upon us and splashing is about to help me out in that department.
Thanks in advance!!

 

[Jimrahbe]

A,

Your CYA is most likely much higher than a "tad".. I say this because often the test stops at 100.

And, because your FC is so low you most likely have an algae bloom, even if you can't see it yet.

Let's see what our other members have to say...

While you wait, you should take a read through our Pool School and see what we are all about. Pool School

Thanks,

Jim R.

 

[Apas]

I tested my cya multiple times and got the same amount. Also took water to the pool store to make sure my measurements were accurate. They got very similar numbers—so I don’t think my calculations are wrong. Couple of years ago, I learned the cya lesson. So I have a fair understanding, I’m no guru, but I’m not clueless either. Pollen has been really high here, so I thought it could be that, but pollen has dropped some and I’m still stuck.

 

[Apas]

A,

Your CYA is most likely much higher than a "tad".. I say this because often the test stops at 100.

And, because your FC is so low you most likely have an algae bloom, even if you can't see it yet.

Let's see what our other members have to say...

While you wait, you should take a read through our Pool School and see what we are all about. Pool School

Thanks,

Jim R.

Thanks. If it’s an algae bloom, wouldn’t the double shock have taken care of that?

 

[Jimrahbe]

A,

Did you do the diluted CYA test? Half pool water and have tap water, then run the normal CYA test and multiply by 2. So if your test shows 60, you actual CYA would be 120.

Thanks,

Jim R.

 

[Jimrahbe]

Shock, by itself, does not kill algae... It might reduce some of it, but it will just come back.

Algae is killed by keeping your FC at the "kill" level for an extended period of time. See this link.. SLAM Process

Thanks,

Jim R.

 

[Apas]

A,

Did you do the diluted CYA test? Half pool water and have tap water, then run the normal CYA test and multiply by 2. So if your test shows 60, you actual CYA would be 120.

Thanks,

Jim R.

Just did. Between 50-60..so 55. But I’m still not understanding why my chlorine won’t get higher. My CC was .5. In the past, when my cya would get high, it never stopped my ability to get a chlorine reading—I know it’s less effective but it was still present. So, I am assuming I need to SLAM based on this? Should I partial drain first and then SLAM?

 

[Apas]

Shock, by itself, does not kill algae... It might reduce some of it, but it will just come back.

Algae is killed by keeping your FC at the "kill" level for an extended period of time. See this link.. SLAM Process

Thanks,

Jim R.

My cc is a .5 do you think I should partial drain first to get the cya down?

 

[MITBeta]

Yes. You should aim to drain 2/3 of your water to get CYA down to 40 or so, then follow the SLAM Process.

Draining - Further Reading

www.troublefreepool.com

You also need to upgrade your test kit to include the FAS-DPD chlorine test.

Test Kits Compared

 

[Mdragger88]

To answer your original question,
You can’t hold chlorine because algae & organics are consuming it.
They were able to proliferate because your fc level fell below the minimum acceptable level for your cya which is likely hard to sustain since your cya is so high.
FC/CYA Levels
Your cya got high because of stabilized chlorine products.
As members above recommended- a water exchange to lower cya & the SLAM Process with liquid chlorine is the cure for the algae. The fas/dpd test is necessary to carry this out.
If you continue your daily chlorination with trichlor tablets after your slam is complete you will be in this situation again. Time for the liquid diet or a saltwater chlorine generator.

How to Chlorinate Your Pool

Before chlorinating your pool, you should know these simple tips. Learn the best way to add chlorine to your pool.

www.google.com

 

[Apas]

Yes. You should aim to drain 2/3 of your water to get CYA down to 40 or so, then follow the SLAM Process.

Draining - Further Reading

www.troublefreepool.com

You also need to upgrade your test kit to include the FAS-DPD chlorine test.

Test Kits Compared

Thanks! I use the FAS-DPD chlorine test. So I’m good to go….off to buy a truck load of chlorine.

 

[MITBeta]

Can you update your signature regarding your test kit?

 

[proavia]

Your signature indicate you have a K-2005 test kit - which does not include the FAS-DPD test reagents. Do you have the R-0870 and R-0871 reagents as an addon? If so, add that to your signature.

Your diluted CYA test provided a result between 50 and 60 - no way to accurately read 55, so round up to 60. Since it was the 50-50 diluted test, that makes your CYA 120. Drain enough water to get your CYA down to around 40-50.

Continued use of tabs/pucks will continue to increase your CYA. Consider a switch to liquid chlorine or a SWG.

Read up on the SLAM Process.
Use the FC/CYA Levels for SLAM level and to keep FC in target range even after the SLAM.
Use PoolMath and share your logs here.