Calcium Hardness Test with TF-100

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Liz315

Bronze Supporter
Jul 12, 2020
330
NJ
Pool Size
15000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
So I just tested my Calcium today with the TF-100 and the first time I had to add 40 drops to get it blue so I did it again and I had to add 41 drops. That has my calcium level very high so I used a test strip and it reads about 300?
I’m wondering if I’m doing the test wrong. Is it when the water turns blue completely after stirring or is it when the drop turns blue when it hits the water.
I have a 15,000 gallon pool and my calcium was at 173 yesterday from the pool store test they had me add 30 lbs of increaser and said to retest today after I added it.
 
40 drops would be a CH of 1,000, so it sounds like something is off. Simply put, use a 10ML water sample. Add 10 drops of #10, then 3 drops of #11, then count each drop of #12 until it goes baby blue. Multiply that number by 25 to get your CH. Take the test strips and place them in the trash. Ha. They are basically worthless. Trust your TF-100. We'll coach you along the way.
 
Yeah so that’s exactly what I did there is no way the calcium is that high right now.
 
If you did the testing as noted above, then your CH must be very high. That could happen if Cal-Hypo was used consistently over a long period as the primary sanitizer. I doubt your local water is that hard, but you can test some water from the hose outside to check and compare.
 
Texas Splash said:
If you did the testing as noted above, then your CH must be very high. That could happen if Cal-Hypo was used consistently over a long period as the primary sanitizer. I doubt your local water is that hard, but you can test some water from the hose outside to check and compare.
Click to expand...
It’s a new pool so only 1 chlorine puck so far so I don’t think that’s the issue. The pool was just filled and it just tested at a 173 hardness prior to the 30 lbs of increaser they told me to add yesterday. Would 30 lbs increase it from 173 to over 1,000?
 
Liz315 said:
Would 30 lbs increase it from 173 to over 1,000?
Click to expand...
No. 30 lbs in a 15K pool would increase the CH by about 215. So as you can see, even the pool store test was not accurate. Without a doubt the TF-100 is the way to go. Tell you what, since this is a brand new plaster pool, next chance you get, post a full set of water test results as follows:
FC
CC
CYA
PH
TA
CH
Water Temp

You can also use the PoolMath APP to load & track your tests. If you do, be sure to go to your profile settings and allow Poolmath to be shown on your TFP profile so we can see your testing. A full set of tests is not only good practice for you as a new owner, but will give us a complete picture of everything.

Below you can find some videos from the TF-100 channel which may help you as well.

www.youtube.com

TF100TestKit

The TF-100 sets the standard for excellence in Pool Testing Kits. It contains 7 separate tests to give you accurate readings on each important pool water par...
www.youtube.com www.youtube.com
 
Thanks, so I test my water for my hot tub and my water source is always low on Calcium hardness which is where they want it to be for my hot tub so it can’t be the water source. Not sure how the calcium hardness could increase so much with what I added then. Is it possible I got an expired batch of the testing drops?
 
Something that might be worth mentioning is my test was pink to start after the drops, not red as it mentions in instructions. Is pink what they are referring to as “red”? Or could that be what’s wrong. If so what would make it pink instead of red.
 

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Try testing your fill water. Not sure what your fill water CH is, but generally, it will be in the 50-200 range. You local water quality report doesn't include water hardness. Not sure of the accuracy, but this link shows some reported levels.

New Jersey – HydroFLOW USA: Award Winning Water Treatment Devices

www.hydroflow-usa.com www.hydroflow-usa.com

Are you using a Speed Stir or Smart Stir. These really help with getting accurate results. The CH test is most sensitive to proper stirring and agitation. A magnetic stirrer will help achieve more accurate and consistent results.

Try swapping the on the R-0012 with a tip from a different reagent bottle.

During the test, hold the hold the dropper completely vertical and squeeze gently so that drops fall off the tip of the dropper bottle. Swirl well between drops.

After adding the R-0011L, the sample will turn pink.

How long did you wait to test after adding CH?

Hopefully you get it figured out.
 
Thanks very helpful. I waited a day after adding the increaser. I did buy a smart stir so I’ll try that later today.
 
Liz315 said:
Something that might be worth mentioning is my test was pink to start after the drops,
Click to expand...
That's normal and indicates the presence of calcium. Use the notes above to try again. Also be sure to post all test results as noted above so we can see everything in the water, not just the CH. Also do a separate test on your fill water source so we can see what that CH is.
 
So I test today using the smart stirrer. Calcium hardness test was 875. My fill water source was 50. So it’s lower than yesterday but adding that 30lbs of increaser raised it a lot. I added some water today because it looked a tad low so maybe that will drop it some. Is 875 terrible on fresh plaster. It’s been 10 days since plaster, 8 days since it was filled totally with water.
I did daily test, very easy. CL/BR: .5/1; Ph raised to 8.2, was 6.3 at pool store on Tuesday.
 
Liz, it sounds as though too much calcium was added previously. CH, just like CYA, doesn't go down just by adding water. You have to actually replace water to lower CH or CYA. Not much you can do for now since the plaster is new and you want it to cure for 30 days. But with a CH so high, you MUST keep the pH managed. I don't see your TA and water temp which play a very important part in your chemistry right now. Here are my suggestions for now:

- If not already, use the PoolMath APP and load all of your test results. Look for a Poolmath profile setting that allows your Poolmath testing to be visible on your TFP profile so we can see everything.
- With high calcium, you MUST watch the pH closely. If it gets too high, you'll get scale. Once you load all your test results and water temp into the PoolMath APP, it will give you a "CSI" number. You want that number around zero (neutral). If it's too high, you will get scale.
- You didn't post your CYA. Look at your last CYA test and compare your FC to the CYA as noted on the FC/CYA Levels. If you let the FC fall too much, you'll get algae.

If you elect to post results, please post them all as follows:
FC
CC
CYA
PH
TA
CH
Water Temp
 
Merged threads. TFP Mod
So I am almost done my 21 day plaster start up. I’m following my pool builders start up so they can’t blame me for anything that goes wrong during this period and then after this Friday I will be moving to the TFP method.
Only things I have added were 30 lbs of
Calcium increaser to get it from 50 to 300. But Since the beginning the tf-100 test was showing calcium extremely high (1,000) where it was testing fine at store and test strips. Then the tf-test slowly started to show calcium coming down (800) the other day then after I swapped the tip to the R-12 bottle is starting to matching up to test strips at 500. I know you guys feel they are junk but I’m using both right now to double check things. All testing methods seem to have issues as there is always room for error and in this case drops being smaller than others.

I guess I’m trying to figure out is could there be any other way besides the drops being too small that could naturally cause the calcium hardness to drop? I have only been managing ph by adding acid besides the initial 30 lbs of calcium increaser.

Is 500 ok? I really don’t want to dump and replace my water. My fill water was at originally at 50. Trying to figure out what is accurate is driving me bonkers. How much would 30 lbs of calcium increaser really raise 15,000 gallons of water?
 
Last edited by a moderator:
Liz315 said:
Trying to figure out what is accurate is driving me bonkers. How much would 30 lbs of calcium increaser really raise 15,000 gallons of water?
Click to expand...
216 ppm.

What sample size are you using for the CH test?
 

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