what causes ch to rise?

mxrider131

Member
Aug 25, 2013
11
Riverside, CA
Just did my first full test with TF-100 kit and noticed mt CH is ridiculously high. Its always been been a little high for the pool store tests (500) but my test shows more than double theres. I've had the pool about 3 years and this is the first time I fully tested it myself. I've only shocked it once in the last year and I just tested CH on my tap water and its only 150. Just wondering if theres something else that would cause it to be that high. Guess I'll be draining my pool.
CYA 20 (currently adding conditioner to raise)
FC 5
TA 50 (currently adding baking soda to raise)
CH 1250! ( I tested it twice and double checked instructions cause i didnt believe it)
ph 7.5
 

RobbieH

TFP Expert
LifeTime Supporter
Aug 30, 2010
4,052
Dallas, TX
There are two common reasons CH rises.
1. High CH fill water
2. Use of Cal-Hypo for chlorination or "shock".

So what have you been using for shocking the pool?

Also, make sure you are adequately stirring the solution when you add the drops. Add them slowly, and stir like crazy. This is where the SpeedStir really comes in handy.
 

RobbieH

TFP Expert
LifeTime Supporter
Aug 30, 2010
4,052
Dallas, TX
CH - Calcium Hardness


Rinse the sample tube with pool water.
Fill the sample tube with pool water to the 25 ml mark. The top of the sample will be curved. This curve is called a meniscus. The bottom of the meniscus should be level with the 25 ml mark.
Add 20 drops of R-0010 and swirl to mix.
Add 5 drops of R-0011L and swirl to mix. The solution should turn red, pink, or blue. If the sample turns blue, you are done and your CH level is zero.
Counting the number of drops as you go, add R-0012 one drop at a time, swirling to mix after each drop.
Continue adding drops until the color changes to something more or less blue. If the sample turns purple see the note on "fading endpoint" below.

Continue adding drops as long as the color continues changing. The final drop, that does not change the color any further, does not count.

If the sample starts to turn blue and then goes back to red/pink and stays there from several more drops this is also a "fading endpoint", see the note below.

Multiply the number of drops by 10 to get your CH level. Remember that the final drop, which didn't cause any further color change, doesn't count.
Dispose of the sample safely. It is best to pour it down the drain with the water running. Do not add it back to the pool.
Rinse the sample tube with tap water and store for next time.

Notes

Hold the dropper bottles vertically and squeeze gently, so that drops come out slowly and seem to hang on the tip of the dropper bottle for a moment before falling.
If you expect that your CH level is extremely high, you can do the test so that each drop is 25, instead of 10, to speed up the process and save on reagent usage. Use 10 ml of pool water, 10 drops of R-0010, 3 drops of R-0011L, and multiply the number of drops of R-0012 by 25 to get your CH level.
Measuring high CH levels is much easier and more precise if you use a magnetic stirrer.
The sample may turn purple during the test, or go to blue for a moment and then turn back to red/pink. This is called a "fading endpoint" and is caused by interference from metal ions. If this happens, do the test again, but this time add five drops of R-0012 before adding any R-0010 or R-0011L. Remember to count the initial five drops in the total.
In extreme cases, a fading endpoint may occur even when adding five drops of R-0012 at the start. If that happens, mix pool water with an equal quantity of distilled water, test that, and then multiply the result by two.
R-0010 is calcium buffer, a strong base which prevents interference from magnesium.
R-0011L is calcium indicator, an organic dye used to provide the red/blue color. It should be a deep blue color. If the dye stains the plastic bottle it is stored in, it has gone bad.
R-0012 is hardness reagent, used to titrate until the color changes.
The precision of the measurement is plus or minus one drop when up to 10 drops of titrant are used, or plus or minus 10% of the final reading, when more than 10 drops of titrant are used.
 

DorsalSpine

Silver Supporter
Jul 8, 2013
483
Columbus, Ohio
RobbieH said:
CH - Calcium Hardness


Rinse the sample tube with pool water.
Fill the sample tube with pool water to the 25 ml mark. The top of the sample will be curved. This curve is called a meniscus. The bottom of the meniscus should be level with the 25 ml mark.
Add 20 drops of R-0010 and swirl to mix.
.
Are you sure about the 20 drops of R-0010? I haven't done this in awhile but I thought it was 2 drops.
 

mxrider131

Member
Aug 25, 2013
11
Riverside, CA
Yes mine says 20 drops of R-0010 and 5 drops of R-0011L. I did 10 drops at a time of R-0012 and used the speedstir to mix it after every 10. Cant remember what i used to shock the pool last time because its been awhile but I'll see if I can find it
 

Butterfly

TFP Expert
LifeTime Supporter
May 30, 2007
10,045
South Carolina
DorsalSpine said:
RobbieH said:
CH - Calcium Hardness


Rinse the sample tube with pool water.
Fill the sample tube with pool water to the 25 ml mark. The top of the sample will be curved. This curve is called a meniscus. The bottom of the meniscus should be level with the 25 ml mark.
Add 20 drops of R-0010 and swirl to mix.
.
Are you sure about the 20 drops of R-0010? I haven't done this in awhile but I thought it was 2 drops.
2 drops is wrong, RobbieH is correct. It is 20 drops of R-0010.

You can confirm in Extended Test Kit Instructions :
extended-test-kit-directions-t25081.html
 

DorsalSpine

Silver Supporter
Jul 8, 2013
483
Columbus, Ohio
Butterfly said:
DorsalSpine said:
RobbieH said:
CH - Calcium Hardness


Rinse the sample tube with pool water.
Fill the sample tube with pool water to the 25 ml mark. The top of the sample will be curved. This curve is called a meniscus. The bottom of the meniscus should be level with the 25 ml mark.
Add 20 drops of R-0010 and swirl to mix.
.
Are you sure about the 20 drops of R-0010? I haven't done this in awhile but I thought it was 2 drops.
2 drops is wrong, RobbieH is correct. It is 20 drops of R-0010.

You can confirm in Extended Test Kit Instructions :
extended-test-kit-directions-t25081.html
Sorry for the confusion, I must have been thinking of a different test. I'll have to remember the extended instructions that are online next time.
 

mxrider131

Member
Aug 25, 2013
11
Riverside, CA
JamesW said:
It might be test error due to copper. Is there any reason to think that there is copper in the water?
There shouldnt be. I tested just the tap water the same way as i tested the pool water and came back with 150. I can test the pool water again trying the copper way and see if it comes up with something different
 

HouTex

LifeTime Supporter
Mar 7, 2011
413
Houston, Texas
Getting back to your original question about what could cause CH to rise, I wonder if it could come from the plaster.

I've been concerned about this with my pool. I've seen my CH rise even when I haven't added tap water (which is about 150 CH) for a couple of months and I never use Cal-Hypo.
 

jjslinger

LifeTime Supporter
Sep 22, 2011
97
Santa Rosa, CA
mxrider131 said:
JamesW said:
It might be test error due to copper. Is there any reason to think that there is copper in the water?
There shouldnt be. I tested just the tap water the same way as i tested the pool water and came back with 150. I can test the pool water again trying the copper way and see if it comes up with something different
You may be in a similar situation to me (my fill water is 140). Evaporation concentrates the CH because water is removed by this process, but calcium stays, and the refill water adds calcium. Splashout on the other hand helps a little because that removes water and calcium which gets replaced by fill water with lower CH, but in my case evaporation slowly "wins" over time, so my CH slowly rises.

I combat this by making my wintertime "pool project" getting as much rainwater in the pool as possible. Since my pool went in in 2011, I have not yet had to do a partial drain/replace to get the CH down, I'm sitting at about 400 right now, and hope to bring that down over the winter.

Don
 

mxrider131

Member
Aug 25, 2013
11
Riverside, CA
Weird thing is I drained about a foot of water from my pool 4-5 months ago for a different reason that the pool store gave me and CH is still this high. Got a good amount of scale build up around surface line of pool and at waterfall (which i thought was normal) and I have to clean SWG like every 4 months and its packed with calcium every time. I guess it makes sense. Just wanted to make sure the other chemicals Im adding (conditioner and borax) to balance my pool didnt give me false readings for my CH. I'm gonna test it again tomorrow and if it comes back the same I'll just have to drain 1/2 the pool and go from there. thanks for the replies
 

y_not

Well-known member
Jul 24, 2012
1,086
Redmond, OR
Are you adding conditioner or stabilizer? It should just be straight powdered cyanuric acid granules, over 95% /w a small amount of inert ingredients.
Adding it by weight, in a sock tied near a return. NOT in the skimmer, or dumped elsewhere. Allow 1 week for it to register on the test, but right away for effectiveness as soon as It's fully dissolved.
Also, are you testing your cya outside, with the tube at waist level, your back to full sun?

Are you following the SWCG guide in PS?
With a CYA of 20 and so much scaling, it doesn't sound like it. Please go read up on it pool school.
Keeping pH in line and scaling to a minimum is immensely critical with an SWCG, even more with plaster in the mix. It can be done at high ch, you just have to stay on it.

Can you post a full set of test results please?
Do this before you make any more changes and we can advise you as to your next and best course of action to take, so as to get things in line.

Thx.
Hang in there! :mrgreen:
 

y_not

Well-known member
Jul 24, 2012
1,086
Redmond, OR
Also, I'd like to point out these specific notes from the extended test kit directions.

If you expect that your CH level is extremely
high, you can do the test so that each drop is
25, instead of 10, to speed up the process and
save on reagent usage. Use 10 ml of pool water,
10 drops of R-0010, 3 drops of R-0011L, and
multiply the number of drops of R-0012 by 25
to get your CH level.
Measuring high CH levels is much easier and
more precise if you use a magnetic stirrer.
 

mxrider131

Member
Aug 25, 2013
11
Riverside, CA
I'm just starting to follow the "water Balance For SWG" guide on this site so im in the process of getting my pool in balance. Since my CYA was less than 20 I added 4lbs of this http://www.lesliespool.com/Home/Pool-Chemicals/Pool-Adjusters/12302.html on Sunday. I followed the instructions on the box and mixed it into a 5 gallon bucket and added it straight to the skimmer return in increments so hopefully that wont screw it up too much. I guess I know better for next time now. I noticed yesterday that my ph and TA were low so I added Borax to increase them. Here are my full test of results i just did

Salt 3600
FC 5
CC 0
PH 7.5
TA 60
CYA 65
CH 1250

are you saying it will be ok to have that high of CH as long as I keep all my other chemicals in balance? Or am i better off just draining half the pool and starting over? I'd like to avoid draining if possible cause its pricey and a pain but I will do it if i need to. thanks for your help
 

duraleigh

Admin
Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
32,859
Sebring, Florida
Keep your pH at or below 7.5 .....no higher.

Have you experienced any calcium scaling to this point?

What is the CH of your fill water?
 

mxrider131

Member
Aug 25, 2013
11
Riverside, CA
I need to make a correction to the FC. I thought the chlorine test thats with the ph one in the kit was FC and the colors must of been a little darker than I thought. I did the actual FC test and it took me 20 drops so my FC is 10. CC is still 0. So its high and might have to do with me raising the cya so much in one sitting. My swg runs at 40% for 7 hours a day right now. If I turn it down to 0% for a day and retest would that be enough to get it down to 5 or does it take awhile to lower the FC? Ch of the fill water is 150. I'll get the pummel stone and clean off the white scaling on the water line and the waterfall from before to see if any new scaling forms.