Help with Chlorine Question

TexasBoy

Active member
Nov 12, 2007
25
Katy, Texas
#1
Hello everybody,


I have a question about chlorine.

My pool is new (finished in January 07) and my chlorine seems to be too low. I am using a salt water system and my salt level is 3750PPM with my chlorinator running at 40%. Do I need to up the percentage on my chlorinator to get my TC to come up?

Air Temp:75 Degrees
Mostly Sunny
FC:3
CC:3
TC:0
PH:8+
Alk:140
Salt:3750

Thanks,
 
G

Guest

#2
I did not see your CYA level nor our calcium hardness. Please post that. Also. FC+CC=TC so your FC 3 ppm, CC 3 ppm and TC 0 ppm is impossible! Your pH and your ALK are both too high for a salt pool! Please read this sticky on water balance for a SWG.

How are you testing your water?
 

tagprod

LifeTime Supporter
Jul 3, 2007
489
Tomball, Texas
#3
I think you have your TC and CC's backwards. Get that PH down and post a CYA reading. Maybe someone can post some insight into that brand of Chlorinator - I'm not familiar with it, but yes if you turned it up to say 60% it would produce more chlorine.
 

JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,879
Silver Spring, MD
#4
Yes, when FC is too low you raise the SWG percentage. When FC is too high you lower the SWG percentage.

I notice that your PH is 8+. You really want to keep your PH below 8.0 at all times.

Also, you list CC as 3 and TC as 0. Since TC = FC + CC, that isn't possible. Hopefully you meant to say that CC was 0 and TC was 3, in which case everything is fine. If CC is really 3 then you will need to shock the pool.

And finally, you didn't mention your CYA level. If you continue to have problems with low FC levels you need to check your CYA level.
 

TexasBoy

Active member
Nov 12, 2007
25
Katy, Texas
#5
I'm using a Taylor K2005 Kit.

My Kit instructs me to take the FC-TC for the Combined Chlorine.

I did invert the numbers on my last post so here are the correct numbers from my test today. I have been adding 1/2 gal of muradic acid every other day to try and lower the PH.


FC: 3
TC: 3
CC: 0
PH: 8+
Alk 140

didn't check for CYA. (out of reagent)

Here are my numbers from a couple of days ago if that helps.

FC:3
TC:3
CC:0
PH: 8+
Alk:150
Cal: 180
CYA: 45

Thanks,
 

duraleigh

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In The Industry
Apr 1, 2007
31,338
Sebring, Florida
#6
Brent,

Your pH needs to come down more quickly than you are doing. I'd suggest adding 1/2 gal followed by 1/2 gal again in an hour and again in another hour (testing each time, pump running) 'til you get it off that 8.0+ mark.

I assume 8.0 is as high as you can measure so you have certainly been much higher than that and may still be.
 

muss08

In The Industry
Mar 22, 2008
56
Maryland
#7
If your CYA is ony 45 then your FC is not that low. Bump up the percentage a bit until you get to about 5 ppm. With your SWG at 40% it is creating chlorine for about 24 minutes every hour. Try bumping it up to 50% (30 minutes/hour) and after a day see where your FC is. Definitely get your pH down. Chlorine is VERY ineffective at that high of pH. Try to get the pH to about 7.2-7.4. With a SWG you will be constantly battling a rising pH.
 

TexasBoy

Active member
Nov 12, 2007
25
Katy, Texas
#8
Thanks for all the help. I will up the percentage on my SW generator and add acid more frequently. I will post again when I get my numbers in line.

The Sticky was also a big help!


Thanks again!
 

duraleigh

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Apr 1, 2007
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#9
Brent,

I really didn't notice the size of your pool 'til now. 1/2 gal of muriatic should have moved your pH VERY significantly....like .6 or more. Something isn't adding up unless your pH was completely thru the roof. How many times have you added 1/2 gallon?

Make sure you are testing correctly and have good reagents. If you're using strips, take a sample to the pool store and get it tested. I would not add more acid 'til you are sure of your test results.
 

TexasBoy

Active member
Nov 12, 2007
25
Katy, Texas
#10
I have been testing the water every 4-5 days and adding a 1/4 to 1/2 gallon of acid every time I test (since Feb 08). My Taylor K-2005 kit consistently reads 8+ PH when I test. The color is a little darker than the marker on the tester. (The marker only goes to 8.)

I tested the PH again this afternoon and it read 7.6. I then took a sample to my pool store and here are their results....

Temp: 85
FC:4.0
TC:4.0
CC:0.0
PH:7.6 ( after adding a 1/2 gallon of acid yesterday afternoon with readings at 8+)
Hardness:180
Alkalinity: 110
CYA:50
Phos:300
Salt 3700

I upped my chlorine generator to 50 but not sure if I really need to. How else do I raise my CC?
 

JasonLion

TFP Expert
Platinum Supporter
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May 7, 2007
37,879
Silver Spring, MD
#11
It is fairly common for PH to rise like that, particularly with TA as high as you have had it. You need to add more acid so that the PH doesn't get above 7.8. Try to keep the PH between 7.2 and 7.8. If you add enough acid to bring the PH down to 7.2 then you should be able to go about the same amount of time and only have the PH go up to 7.8.

You don't want to increase CC, you want CC to stay at zero. You do want to increase FC slightly. You do that by increasing the SWG percentage, just as you have already done.

It would be better if you increased CYA a little, to somewhere between 60 and 80, by adding some stabilizer. That would allow you to lower the SWG percentage while maintaining the FC level, reduce the rate at which the PH rises, and increase the cell life of your SWG.
 
G
#13
Bgraeter said:
I'm using a Taylor K2005 Kit.

My Kit instructs me to take the FC-TC for the Combined Chlorine.
That should be TC (total chlorine) - FC (free chlorine) = CC (combined chloramines) FC is always going to be equal or less than the TC and CC cannot be a negative number.