First test with the TF-Pro...Calcium harness test question (Instructions and video have different quantities)

[mdshahan]

Just got the TF-Pro test kit and ran all the tests I could. Two tests (CH and TA) had vastly different numbers than the last "Leslies Store" test and I noticed that the included instructions for performing Calcium Hardness tests are different than the example videos on YouTube. (

) My calcium hardness seems very high, especially since my last Leslies test 10 days ago had CH at 226, and I've mainly been adding liquid chlorine since then.

Here's my last results OR Pool Math Log (couldn't test Combined Chlorine yet due to lack of R-0003)
FC 2.5
pH 7.6
TA 160 (Leslies 10 days ago was 87)
CH 1125 (Leslies 10 days ago was 226)
CYA 55 (Leslies 10 days ago was 86)

For CH test, TF-Pro instructions say:

• 10 ml pool water
• 10 drops R-0010
• 3 drops R-0011
• R-0012 until blue, then multiply by 25

Video says:

• 25 ml pool water
• 20 drops R-0010
• 5 drops R-0011
• R-0012 until blue, then multiply by 10

I did the CH test a few times, thinking I was doing something wrong...are the quantities and multiplication values listed in both the written and video correct?
I had to add about 45 drops of R-0012 before I thought the test was really "blue". I was also using the Speedstir on the that test. I tried one without the Speedstir, but it seemed like the reagents weren't mixing that great and I'd see a bunch of pink "particles" forming as I added R-0012...this is the first time doing any test like this so I'm not sure if that's normal and just needed more agitation?

Was also surprised by the TA being double? That test seemed easier to perform and notice the color change than the Harness test, so I don't think I was that far off in testing?

Pool water sample was around 80 degrees and I was performing the tests outside...outside temp was around 95 degrees, but I was in the shade the whole time after taking the water sample. Could the ambient temperature affect these test so severely?

Thanks all,
Michael

 

[mknauss]

First TA test with R0009 can be small drops. Be sure to read Total Alkalinity - Trouble Free Pool
But I would not be surprised if your TA is not much higher than what a pool store would report. They consistently report low TA.

The CH instructions you show above are correct. Again, be mindful of the drops using the R0012. Bottle vertical, no or little pressure on bottle, each drop should form and drop naturally. About one second per drop.

 

[wireform]

Regardless, trust your own testing once you get it figured out.

 

[mdshahan]

OK, re-ran some tests today and CH still came out higher than I'd expect (625), but much better.
TA is still coming in around 150, so surprised that it could be so far off from the stores test, but I've run it multiple times so I'll assume the TF test is more accurate.

I see the recommendation is to lower pH and aerate, so need to look up how to aerate a 35,000 gal pool

 

[mknauss]

If you simply reduce your pH to 7.2 when it gets to 7.6 or so, the TA will come down. You may be adding acid every other day depending on how much fill water you add.

 

[Rancho Cost-a-Lotta]

CH still came out higher than I'd expect (625)

How long has it been since you filled or drain and refilled your water? Since calcium does not evaporate from the pool, CH will continue to rise with evaporation and top-offs. This may explain why you are seeing higher than expected levels.

Try testing the CH of your fill water. This may give you a clue as to why your CH is as high as it is. Testing the TA of your fill water will give you an idea of how your pool's TA will change with top offs.

I see the recommendation is to lower pH and aerate, so need to look up how to aerate a 35,000 gal pool

If you have an attached spa, you can set your returns to spa with suction from pool. The combination of the spa bubbles and spillover will expedite aeration. Waterfalls and water features help also.

 

[mdshahan]

Thanks for the suggestions...good idea to test the fill water CH and TA. About 3 weeks ago is when I started the process of learning how to handle our own chemicals, etc. Over the first week I drained approximately half the pool water and was testing at the local Leslies (didn't have our own kit yet) until their numbers looked good. The TA and CH numbers from their tests 11 days ago were much lower than I'm reporting and I've only topped off a couple inches since then. Their CH reading was 226 vs 625 and TA was 87 vs 150.
I know members say store tests can be unreliable...I'm just surprised there's such a big difference.

 

[mknauss]

The Vacaville Water Dept indicates the average CH of the water they supply is 183 ppm. So unless you use softened water for make up water, there is no way your pool water CH would only by 226ppm. You do not get overflow from rain all that often.

TA from pool stores is adjusted TA. TFP does not adjust anything. Poolmath manages that in the background. A portion of your total TA is cyanurate alkalinity. The pool store numbers attempt to remove that from their 'total' alkalinity.

 

[mdshahan]

The Vacaville Water Dept indicates the average CH of the water they supply is 183 ppm. So unless you use softened water for make up water, there is no way your pool water CH would only by 226ppm. You do not get overflow from rain all that often.

TA from pool stores is adjusted TA. TFP does not adjust anything. Poolmath manages that in the background. A portion of your total TA is cyanurate alkalinity. The pool store numbers attempt to remove that from their 'total' alkalinity.

Didn't know about "adjusted TA"...good to know the store tests are basically reporting a different number.

 

[mdshahan]

As for lowering TA...I added a bit of Muriatic Acid this morning, and a bit more this evening...pH is about 7.4 now. Should I wait to start aeration until the pH measures around 7.0?
Then try and bring pH back up a bit and repeat until TA is in range?

 

[mknauss]

When your pH rises to 7.8, lower it to 7.2. No real reason to mess with aeration. Just manage the pH. Test pH every other day or so for awhile. Be sure to test TA whenever you need to add acid. That value is needed in Poolmath to tell you how much acid is needed.

 

[mdshahan]

The Vacaville Water Dept indicates the average CH of the water they supply is 183 ppm. So unless you use softened water for make up water, there is no way your pool water CH would only by 226ppm. You do not get overflow from rain all that often.

TA from pool stores is adjusted TA. TFP does not adjust anything. Poolmath manages that in the background. A portion of your total TA is cyanurate alkalinity. The pool store numbers attempt to remove that from their 'total' alkalinity.

I tested our fill water tonight...kind of surprised by the pH, but I tested with both a digital meter and the TP-Pro pH test. Here's what I found:
pH 8.4
CH 75
TA 170