Battling low chlorine levels all summer

hensler74

Gold Supporter
Sep 16, 2021
189
Fort Worth TX
Pool Size
11250
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Jandy Aquapure 1400
So I have been battling my chlorine levels all summer long and cannot seem to figure it out. I started thinking my SWG might not be working properly but I have no errors on it and had a company out on 6/2/2023 and they said they could not see anything wrong with it. SWG was put on in September 2022 so it is not even a year old.
We have only been pool owners for 3 summers now and I have done very good keeping it up until this summer. Looking for any help I might could get as to why I cannot get my chlorine levels up higher.
Pool is crystal clear.

Here is some information about the pool & spa.
Location - Fort Worth TX
11,400 gallons
SWG is a Jandy PLC1400 and is set to 80% for the last two months
Last test done at Leslie's Pool on 7/22
FC was 0.13
TC was 0.38
PH 7.6
TA 111
CH 209
CYA 47
Salt 3185
 
Hi but without your signature filled out it would be difficult to see all and everything about your pool. Your main problem is the poolstore as we don't offer advice on their testing.
please read
Test Kits Compared
Sorry about that. I have updated my signature. I do use the Taylor 2500 test kit when testing at home. I was out of town this past week so could not test so the wife took a sample to the pool store. I can tell you when I tested last time using the Taylor 2500 by FC less than 1 and so was the CC, PH was 7.8, CYA was 50, TA 140 and I did not do a Calcium test that day for some reason.
I can perform a test when I get home today but do know the FC & CC will be higher because the wife shocked it Saturday night.
 
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Which test kit do you actually have? The one that you list is close to Taylor K-2005 (K-2500 doesn't exist). This test kit is almost complete, but does not have the chlorine drop test (K-1515). This is truly what's required for accurate measurements and getting your SWG output dialed in.

If your chlorine has been allowed to drop to low levels as noted, you may have algae. You need to complete an Overnight Chlorine Loss Test but you do need the proper FC drop test.

To stabilize things for now, get your FC to 5 ppm with liquid chlorine and hold it there daily until you can complete the OCLT.
 
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Which test kit do you actually have? The one that you list is close to Taylor K-2005 (K-2500 doesn't exist). This test kit is almost complete, but does not have the chlorine drop test (K-1515). This is truly what's required for accurate measurements and getting your SWG output dialed in.

If your chlorine has been allowed to drop to low levels as noted, you may have algae. You need to complete an Overnight Chlorine Loss Test but you do need the proper FC drop test.

To stabilize things for now, get your FC to 5 ppm with liquid chlorine and hold it there daily until you can complete the OCLT.
Sorry my fat fingers it is the K-2005 not 2500. I guess I need to get the other stuff needed so I can do the OCLT.
 
Yes. The OTO FC test in the other kit does not do a good job of pinpointing levels and only reads FC levels up to 5 ppm.
So I have never used or purchased liquid chlorine before. Any recommendations on brand to buy so I can get it and do the calculations to get FC up to 5 ppm until my other test kit comes in which will be Wednesday. Also is it ok for people to swim while waiting to perform the overnight test
 
I get mine (when I need it) from a local pool store in refillable jugs (HASA Brand12.5%) You can get 10% from Walmart, HD, Lowes Ace, Pinch-a-Penny etc. It may sold as Liquid Shock or Chlorinating Liquid. The label should read sodium hypochlorite (10% or 12.5%)
 
I get mine (when I need it) from a local pool store in refillable jugs (HASA Brand12.5%) You can get 10% from Walmart, HD, Lowes Ace, Pinch-a-Penny etc. It may sold as Liquid Shock or Chlorinating Liquid. The label should read sodium hypochlorite (10% or 12.5%)
Thanks the percentages is helpful to walk in to a store and tell them what O am looking for.
 

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Keep FC at 5 ppm and you should be safe to swim.
So I finally got all the proper testing stuff that is needed. The Taylor K-1515 and the K-1766 for Salt (already had the K-2005) and a SpeedStir . I did my first test with these today and it did not seem good to me as I have been doing my best with just the K-2005 to keep FC around 5 until I got these test kits in. Below are the results and here are a few questions I have so I can try to perform a OCLT tonight to figure out my issue.
1. Should I adjust my PH before added liquid chlorine for my OCLT?
2. Should I adjust my TA before the test?
3. Is in regards to the Salt level, as my SWG is reading 3200, my K-1766 is reading 3800 and I have a eSeasonGear Salt-3000 digital salt meter that is reading 3440. Which should I use for my test results.
Any and all help would be appreciated as I am new to TFP but want to learn as much as I can.


7/27/203 readings
FC - 1
CC - 0.5
PH - 8
TA - 120
CH - 290
CYA - 40
Salt - depends on which reading I use from question 3 above.
Temp - 92
CSI - 0.46
 
Go ahead and adjust pH. Add enough muriatic acid to lower pH to 7.2. When you add MA it will also lower TA. Leave the salt level where it's at. As long as your SWG is not displaying any warning lights, you should be good for now. It's common to have a disparity in salt readings between different devices.
 
Go ahead and adjust ph. Add enough muriatic acid to lower pH to 7.2. When you add MA it will also lower TA. Leave the salt level where it's at. As long as you're swg is not displaying any warning lights, you should be good for now. It's common to have a disparity in salt readings between different devices.
Thank you, How long after adding MA should I wait to test it again? I will go add MA now to adjust to 7.2 and then start my test at sundown and will post results in the morning of sundown and before sunrise results. Appreciate your reply.
 
For now, add enough liquid chlorine to increase FC 5 ppm. Allow the chlorine to circulate in the pool for about 15 minutes, then add MA. After sunset, test FC for the OCLT. Then test again before sunrise. If you get it done soon, and if my calculations are right, you should have about 45 minutes of good circulation time before your post-sunset test.

As a side note, liquid chlorine and MA combined can create a hazardous gas. You want to wait about 15 minutes between adding one or the other.
 
I probably don't have to say this, but make sure the SWG is shut down between the two tests. Make sure the water is circulated well before the pre-sunrise test. Take your time with the FC test. Make sure the bottle is completely vertical and allow the drops to just fall off the tip.
 
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For now, add enough liquid chlorine to increase FC 5 ppm. Allow the chlorine to circulate in the pool for about 15 minutes, then add MA. After sunset, test FC for the OCLT. Then test again before sunrise. If you get it done soon, and if my calculations are right, you should have about 45 minutes of good circulation time before your post-sunset test.

As a side note, liquid chlorine andA combined can create a hazardous gas. You want to wait about 15 minutes between adding one or the other.
Guess I should have waited for your reply. I added the MA already so am I good to wait 15 minutes then add the liquid chlorine? Will I need to adjust the PH again after I add the liquid chlorine I am guessing?
 
For OCLT to be valid, FC should be 3 or greater when you start. If you are below that when you start OCLT, add chlorine, circulate for 30 minutes and re-test.

Open weather on your phone. Note sunset and sunrise times. Test after sunset tonight and before sunrise tomorrow.
 
For OCLT to be valid, FC should be 3 or greater when you start. If you are below that when you start OCLT, add chlorine, circulate for 30 minutes and re-test.

Open weather on your phone. Note sunset and sunrise times. Test after sunset tonight and before sunrise tomorrow.
Yes sir I already noted that, sunset is 8:32 tonight and sunrise is 6:40. I was concerned if I should adjust the PH prior to getting FC to 5? Rancho suggested I should but then stated to add chlorine first but I was already adding MA for the PH.
 
It doesn't matter what order you make your adjustments. I just suggested FC first so the chlorine would have more time to circulate prior to your OCLT test. However, you should have plenty of time. Adjusting pH will have no effect on FC. No sweat.
 
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