New pool owner with high Chlorine questions..

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J

jtb777

Bronze Supporter
Aug 19, 2022
93
California
Pool Size
27000
Surface
Plaster
Chlorine
Liquid Chlorine
Hi all,

I'm a new pool owner (in ground) and I'm really concerned about high chlorine levels. Can I please get some advice on getting these levels down?

I have a LaMotte ColorQ Pro-7 test kit, and I've had to dilute samples of water because it keeps saying "Hi" on the reading. Yesterday, a pool store tested my sample and they showed 15 for both free and total chlorine.

Today's Readings:
FCL: 14.36 (test sample 1/2 pool water, 1/2 filtered water)
TCL: 15.7 (test sample 1/2 pool water, 1/2 filtered water)
pH: 7.6
Alkalinity: 43
Calcium Hardness: 276
CYA: 76

How long should it take for chlorine levels to go back down? I've removed the floater that had 3" chlorine tabs. It's been 24 hours since my last test (yesterday), and I'm surprised the level hasn't dropped more.

Also, can I do anything else besides waiting it out to get this level down? My pool is in direct sun and I've removed the chlorine tabs.

Thank you so much for any help you can provide!
 
Last edited:
Welcome. Two key points on your post:

1. Digital testing is not recommended as it can be way off, especially if not calibrated on a regular basis. See the pool school link for recommended test kits. They do not have the bells and whistles as digital testing, but they are much more reliable and consistent.
2. There are 2 schools of thought on chlorine levels:
  • Keep your chlorine between 1-4. Simple, yet outdated thinking. Unfortunately, a lot of literature and products still have this old school thinking, including your digital tester.
  • There is a relationship between your CYA and your FC and your CYA level determines your FC ranges. This is what TFP teaches. See the FC/CYA chart in my signature to better understand the relationship between these 2 measurements.
To answer your specific questions.
- Most pools lose between 3 and 5 FC per day, so your 15 FC could be completely gone in a few days. Keep in mind that 15 may be high, low, or just right for your pool, it really depends on your CYA levels.
- I wouldn't do anything to lower your chlorine, let it naturally lower to whatever your range should be for your CYA.

Hope that helps. I tried to keep to the highlights, but there is a lot to learn in pool school and usually takes people a while to catch on so do not be shy with the questions.
 
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The chlorine loss to sun could be slowed by high CYA. You will want to get a test kit to test yourself where your pool is at.

www.troublefreepool.com

Swimming Pool Test Kits Compared

What pool test kit should I buy? Why not use test strips? Our recommended test kits will pay for themselves in no time!
www.troublefreepool.com www.troublefreepool.com
 
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JJ_Tex said:
Welcome. Two key points on your post:

1. Digital testing is not recommended as it can be way off, especially if not calibrated on a regular basis. See the pool school link for recommended test kits. They do not have the bells and whistles as digital testing, but they are much more reliable and consistent.
2. There are 2 schools of thought on chlorine levels:
  • Keep your chlorine between 1-4. Simple, yet outdated thinking. Unfortunately, a lot of literature and products still have this old school thinking, including your digital tester.
  • There is a relationship between your CYA and your FC and your CYA level determines your FC ranges. This is what TFP teaches. See the FC/CYA chart in my signature to better understand the relationship between these 2 measurements.
To answer your specific questions.
- Most pools lose between 3 and 5 FC per day, so your 15 FC could be completely gone in a few days. Keep in mind that 15 may be high, low, or just right for your pool, it really depends on your CYA levels.
- I wouldn't do anything to lower your chlorine, let it naturally lower to whatever your range should be for your CYA.

Hope that helps. I tried to keep to the highlights, but there is a lot to learn in pool school and usually takes people a while to catch on so do not be shy with the questions.
Click to expand...
Thanks for your reply! I'll take a look at the recommended test kits. I just bought the Lamotte ColorQ because I have problems seeing colors correctly, but I really want to get accurate readings.

I really appreciate the explanation on the CYA and FC relationship. I hadn't heard of that until now. Everything I had read said FC between 1-4 and that anything over 10 is dangerous. I've been staying out of my pool because of that.

So looking at the chart, it seems like FC should be between 9 to 11 for a CYA 76. If I don't try to lower chlorine, should I put the floater with chlorine tabs back in the pool? Would that still lower even with the floater in there?

Lastly, looking at the chart you shared, it seems like a CYA of 70+ is not recommended. If I'm at 76 (assuming that's accurate), should I look into getting this level lower?

I really appreciate your time!
 
mknauss said:
IF that test data is correct, the FC is not high. It is slightly above target for your CYA, but well below SLAM level. Go swimming

I would suggest you consider getting a proper test kit.
Test Kits Compared
Click to expand...
Thanks for your reply. I don't have enough experience yet to understand what is only slightly above target for CYA 76 and what would be too high. So if 15 (assuming that's accurate) is slightly above, what would be the level where I should actively try to lower the chlorine? Looking at the chart, it seems like I should be between 9 and 11.

Also, I'm not familiar with SLAM, but I'll take a look around to find out what's that about.

I very much appreciate the help!
 
The real problem is that you have no idea what any of your chemical levels truly are. That ColorQ reader still just reads test strips, which are notoriously bad at telling you the correct levels.
 
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For CYA you round up to the 10’s so CYA 76 would be considered CYA 80. Using tabs will raise your CYA so you would be better off using liquid chlorine.

When they mention SLAM levels of FC (used to clear algae) they are just saying any FC up to that level is SAFE to swim in…so you do not need to stress that your FC is over recommended or ideal. You can let it go down naturally to keep FC under 10 so your pH tests are reliable and save yourself some chlorine 😃. I would recommend you keep a safe buffer from minimum FC though…whatever your FC loss for the day is make sure that your FC is still about at least 2ppm above that minimum so you never go below because real life does not exist in a sterile test tube lol.
 
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What is the delivery time on on TFTestkits? The reason I did not order the TFPro from there is I did not get any delivery dates & Amazon gave me a quick delivery date (and bought the SpeedStir) since I wanted to have it before pool opened. Will be good for me to know for next year.
 
Britali said:
What is the delivery time on on TFTestkits? The reason I did not order the TFPro from there is I did not get any delivery dates & Amazon gave me a quick delivery date (and bought the SpeedStir) since I wanted to have it before pool opened. Will be good for me to know for next year.
Click to expand...
Mine came within the week. I think I ordered on a Sunday and it arrived either Wednesday or Thursday of the same week.
 
Britali said:
For CYA you round up to the 10’s so CYA 76 would be considered CYA 80. Using tabs will raise your CYA so you would be better off using liquid chlorine.

When they mention SLAM levels of FC (used to clear algae) they are just saying any FC up to that level is SAFE to swim in…so you do not need to stress that your FC is over recommended or ideal. You can let it go down naturally to keep FC under 10 so your pH tests are reliable and save yourself some chlorine 😃. I would recommend you keep a safe buffer from minimum FC though…whatever your FC loss for the day is make sure that your FC is still about at least 2ppm above that minimum so you never go below because real life does not exist in a sterile test tube lol.
Click to expand...
I really appreciate this explanation, and thank you for the tip on using liquid chlorine. When letting FC levels come down naturally, would that mean not chlorinating until levels are back to what they should be? In other words, should I pull out my floater with tabs or not using the liquid while levels are high? Again, this is assuming I'm getting correct readings (my new test kit is on the way).

Thanks for the help!
 
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I just wanted to ask another related question.. Should I be shocking my pool every 1 to 2 weeks? I'm still finding my way around this forum, so I apologize if it's already been answered. Thank you all again for jumping in and helping me!
 

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