The last few times I have tested my pool the free chlorine is low, but the total chlorine is high. How can I get them aligned? This is a saltwater system, gunite in ground pool.
Low free chlorine, but high total chlorine
- Thread starter TomEnMS
- Start date
How are you testing? High CC is something brewing in the water. Tell us what's been going on.
- Feb 6, 2015
- 7,813
- Pool Size
- 12300
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
Welcome to posting on TFP! 
How are you testing your pool water (what test kit)?
At TFP, we are keen on pool owner self testing with a high quality drop based test kit.
Test Kits Compared
FC +CC = TC
We are only interested in FC and CC.
TC is meaningless without knowing what FC and CC are.
Post a full set of current test results from one of the recommended test kits.
FC
CC
pH
TA
CH
CYA
Salt
Water temperature
How are you testing your pool water (what test kit)?
At TFP, we are keen on pool owner self testing with a high quality drop based test kit.
Test Kits Compared
FC +CC = TC
We are only interested in FC and CC.
TC is meaningless without knowing what FC and CC are.
Post a full set of current test results from one of the recommended test kits.
FC
CC
pH
TA
CH
CYA
Salt
Water temperature
I have been using test strips. After watching the video, I need to purchase a good drop based kit. I am looking for TFPs recommendations.
Get the TFPro. It has the best bang for the buck and has the speed stir in it. Get the salt test addition as well. Get yourself some liquid chlorine so you can get it into the pool as the SWG isn't going to give you a bunch of FC at once, which is what you need. Put 1/3 to 1/2 gallon in each day until you can test with the new kit. Then post all of the water tests.
+3 for the TFpro salt.
I broke down the deets here :
www.troublefreepool.com
I broke down the deets here :
Looking to buy a test kit, need advice...
I am looking to buy a test kit. My pool details are provided below: 13,500 Gallons Pebble Finish Jandy 2.7 HP VS FloPro Jandy 200 Sqft Cartridge Filter Jandy TruClear SWG Jandy 103k BTU VersaTemp Heater K-2006C-SALT Test Kit (Planned). I have researched this topic briefly and am interested in...
www.troublefreepool.com
TFPro ordered. I picked up 2 more gallons of liquid chlorine and will add it. Thanks for the help. I'll post the test results when I get the kit.
I got my TFSalt Pro in. My pH was off scale high. I added a gallon of muratic acid and will retest.
FC = 4
CC = 0
CYA - the black dot never gets obscured. I need a better way to add stabilizer. When I pour it through the skimmer it plugs my filter (5 micron cartridge). What do you recommend.
TA = 110
Cl Br = 2-4
CH = 200 ppm
SWG = 3600 ppm
FC = 4
CC = 0
CYA - the black dot never gets obscured. I need a better way to add stabilizer. When I pour it through the skimmer it plugs my filter (5 micron cartridge). What do you recommend.
TA = 110
Cl Br = 2-4
CH = 200 ppm
SWG = 3600 ppm
Katodude
Silver Supporter
- Aug 22, 2017
- 3,002
- Pool Size
- 15000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
Read up on the sock method.
Basically hang a sock full of stabilizer in front of the return. Squeeze the sock occasionally.
Basically hang a sock full of stabilizer in front of the return. Squeeze the sock occasionally.
Only add 30 CYA and then Overnight Chlorine Loss Test.
If you pass then you can raise the CYA the rest of the way to 70. Or maybe split the difference because it's the late season and everyone's UV demand is much less these days.
Here's how I add CYA.
www.troublefreepool.com
If you pass then you can raise the CYA the rest of the way to 70. Or maybe split the difference because it's the late season and everyone's UV demand is much less these days.
Here's how I add CYA.
How to add large batches of CYA
Hey Folks !!! With a large pool, I need 4lbs of CYA to only raise it 15, and I don't think I have that many socks without holes in them. So I use a Tshirt. Plus, I like that it's doubled up for redundancy. But it can also be scaled down with socks. So I measure out my dose and...
www.troublefreepool.com
Things are getting better. I need to add Calcium Hardness Increaser to get my Cl & Br down from off scale high, but don't know how much. I need to add more stabilizer too. I've added 3 gallons of liquid, and will try the sock method once I get numbers where they should be. Here are the latest results:
FC=15
CC=0.5
CYA=50
TA=07
Cl & Br are both off scale high. I will add Calcium Hardness Increaser.
pH=7.5
CH=175
SWG=2400 - I will add salt today too.
Thanks for all the advice. My pool never looked bad except for some algae patches, so I was happy with the guess strips. I have learned the lesson.
FC=15
CC=0.5
CYA=50
TA=07
Cl & Br are both off scale high. I will add Calcium Hardness Increaser.
pH=7.5
CH=175
SWG=2400 - I will add salt today too.
Thanks for all the advice. My pool never looked bad except for some algae patches, so I was happy with the guess strips. I have learned the lesson.
- Jun 24, 2021
- 15,986
- Pool Size
- 29000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60 Plus
Calcium Chloride does not lower FC. Turn down your SWG or stop liquid chlorine addition. FC will come down on its own.
Calcium Chloride raises CH.
Also, it's Cl *or* Br, one or the other not both. Ignore the block test as it doesn't give you a value and is vague at best. Down the road when you're at one with the pool and are all but certain you have enough FC to make it through the next UV loss cycle, then fine, taxicab yellow probably confirms your suspicion. 
- Jun 7, 2024
- 410
- Pool Size
- 7300
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- Intex Krystal Clear
New numbers 10/25
FC=23 (I plan to cut back on my generator)
CC=0
CYA=90
TA=90
Cl=Off scale high
Br=Off scale high
pH=8.2 (I'll add 1 gallon muriatic acid)
CH=225 (I'll add calcium chloride)
SWG=3600
Pool looks great. I am just concerned about Cl & Br both so high.
TomEnMS
FC=23 (I plan to cut back on my generator)
CC=0
CYA=90
TA=90
Cl=Off scale high
Br=Off scale high
pH=8.2 (I'll add 1 gallon muriatic acid)
CH=225 (I'll add calcium chloride)
SWG=3600
Pool looks great. I am just concerned about Cl & Br both so high.
TomEnMS
Turn it off for now.
Is the pool covered?
If yes, leave it uncovered.
22.4 oz 3% hydrogen peroxide will lower the FC by 1 ppm if you feel like you need to lower the FC some or just wait it out.
7 quarts H2O2 will lower the FC by 10 ppm.
High FC makes the pH test invalid.
Last edited:
- Jun 24, 2021
- 15,986
- Pool Size
- 29000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60 Plus
Do NOT add a gallon of muriatic acid. That will lower pH by 3.1.
Your pH test is not valid when FC >10.
CH of 225 is fine. Test your fill water CH.
Your pH test is not valid when FC >10.
CH of 225 is fine. Test your fill water CH.
- Sep 23, 2015
- 2,012
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Astral Viron V25
Take note of @Newdude’s post #14.
Don’t worry about the Cl and Br from the OTO side of the pH comparator. pH comparators all come double sided, your comparator is a Cl/Br OTO and pH combo. OTO can be used for both chlorine (Cl) and Bromine (Br) but any pool or spa will only be one or the other, never both. There is no bromine in your salt pool. Your OTO test result is just telling you that your total chlorine is 5ppm or higher which is no surprise since your FAS/DPD free chlorine (FC), pink to clear, test gives you a result of 23ppm. By now you should be familiar with TFP’s FC/CYA Levels where we dont consider 5ppm FC high in the presence of 90ppm of CyA. Dont let that get any higher - no stabilized chlorinated products or stabilizer.
It can be a little confusing in the beginning but you’ll quickly get the hang of it. There are three types of chlorine tests, OTO (shades of yellow), DPD (shades of purple) and the FAS/DPD (a pink to clear titration). Just ignore the OTO test for now. Its best use is as a spot check to see if you have chlorine and when used in that way with TFP principles you always want it to be a dark taxi cab yellow to say yes I have chlorine but it wont tell you how much.
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