Help! Chlorine Stabilizer levels continue to fall

Kevman808

Gold Supporter
Mar 13, 2021
23
Davenport, IA
Pool Size
17000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Hayward Turbo Cell (T-CELL-5)
Hello, I installed a pool last year and had no issues with the balancing of the water. Saltwater chlorinator ran at 35% and water stayed clear.

I opened the pool this year early before any algae grew, ran the super chlorinate function for a few days, tested my water and balanced it and had clear water for the first month. After we had a few big swim weekends I noticed it starting to get cloudy, so I would run the super chlorinate function but it didn't clear up.

I started testing the water daily and there was almost no chlorine in the pool and the stabilizer was almost at zero. But, if I held a test strip over the jet, it showed that chlorine was coming out. So my thought was that the low stabilizer was allowing the chorine to get eaten by the sun and the chlorinator couldn't keep up. I bought the appropriate amount of stabilizer and added it to the pool again (Last year I only added stabilizer once all year). My stabilizer reading climbed back up to 60, but within a week it was back down to zero. During that time I had added liquid chlorine to clear the cloudy pool and got my chlorine levels back and added more stabilizer.

I continued to test every day and sure enough, the stabilizer fell down to zero. I also noticed during this time that the chlorinator would turn off from time to time and wouldn't produce chlorine. I would turn the chlorinator down to zero to where I could hear it click off, then crank it back up to 100% and it would turn on. I would then put a strip over the jet and see that it was producing chlorine.

At this point it feels like I have a problem with something destroying my stabilizer and also my chlorinator not running as it should.

I read on a few different forums that some bacteria can get in a pool over the winter and destroy stabilizer. Since it's a fiberglass pool, the water stays in the water all year (I live in Iowa). So I followed your guy's shock method and got the FC levels up to 30-40 two times over a 2 day period. I added stabilizer again during this period and got my levels to the following 4 days ago:

FC=3
PH: 7.2
Alkalinity: 120
Calcium: 160
CYA=60

Pool looked crystal clear for the last 4 days and I just used the strips each day to make sure there was still chlorine and stabilizer. This morning I put the strip in and it showed almost no chlorine and I noticed the water was not as clear. I pulled out the test kit and tested the stabilizer and it read 38-40. Also, when I put the strip over the jet no chlorine was coming out.

I have a call into a pool company to troubleshoot my chlorinator, but I wanted to post here to you guys to help me with my chemicals. Feel free to help on the chlorinator as well! Why is my stabilizer falling? I've shocked it, I've added probably 20 pounds of it this year and raised the levels up to the acceptable range twice. Last year I had none of these issues and I cannot figure out what I'm missing!

Thanks a million,

Kevin
 
It sounds like you need to get a proper test kit including a salt test kit.
Test Kits Compared
Hello, Taylor K 2006C is not a proper test kit? I got that recommendation from this site I believe when I bought the pool.

I do have a salt test and it reconciles accurately with my Aquaplus salt sensor. 3400 right now.
 
I am sorry I did not read that you had a proper test kit. I saw strips used for fc and cya.
 
So I followed your guy's shock method and got the FC levels up to 30-40 two times over a 2 day period
That is not The TFP method for ridding your pool of algae & u didn’t hear it here.
We advocate the SLAM Process based on the FC/CYA Levels.
Not dumping in extreme amounts of chlorine randomly which risks damage to surfaces, equipment, & swimmers.
Use your k2006 - not strips. They will lead u astray.
Cya is measured in increments of 10ppm so anywhere between 30 & 40 counts as 40.
It sounds like u may have multiple issues going on but 1st things 1st -
Do an Overnight Chlorine Loss Test to rule out algae.
If u pass, increase your stabilizer to 70.
& chlorinate accordingly with liquid chlorine FC/CYA Levels & then we can troubleshoot your swg issues.
If u fail - follow the SLAM Process.
 
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That is not The TFP method for ridding your pool of algae & u didn’t hear it here.
We advocate the SLAM Process based on the FC/CYA Levels.
Not dumping in extreme amounts of chlorine randomly which risks damage to surfaces, equipment, & swimmers.
Use your k2006 - not strips. They will lead u astray.
Cya is measured in increments of 10ppm so anywhere between 30 & 40 counts as 40.
It sounds like u may have multiple issues going on but 1st things 1st -
Do an Overnight Chlorine Loss Test to rule out algae.
If u pass, increase your stabilizer to 70.
& chlorinate accordingly with liquid chlorine FC/CYA Levels & then we can troubleshoot your swg issues.
If u fail - follow the SLAM Process.
Thank you! I will do all this tonight. I swear when I read the slam process I followed the chart to a T. Based on a salt water pool and the amount of stabilizer in the pool, it said I needed at least a chlorine level of 20-25 so I got it up to 30.

I must be wrong, so will check when I get home from work.

Kevin
 
Thank you! I will do all this tonight. I swear when I read the slam process I followed the chart to a T. Based on a salt water pool and the amount of stabilizer in the pool, it said I needed at least a chlorine level of 20-25 so I got it up to 30.

I must be wrong, so will check when I get home from work.

Kevin
Going over slam level for your cya just wastes chlorine & risks damage to surfaces, equipment & swimmers.
SLAM stands for Shock Level And Maintain. It is not just one or two times of raising fc to shock level but Maintaining that level until u pass ALL 3 end of SLAM Process criteria as mentioned in the article. This ensures you have eradicated ALL the algae & that it won’t return if you maintain proper fc levels for your cya thereafter. This means testing & replenishing fc multiple times per day.
Knowing your correct cya level is quite important to the process. As Too little chlorine doesn’t quite do the trick but too much is a waste & gets burned off quickly. Be sure to test cya with your kit outdoors with your back to the sun ☀️, a sunny day is best. You can pour the solution back into the squirty bottle & repeat the test multiple times to get an average.
 
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