Test kit results way off from what pool store says

kikipunx

Member
May 9, 2020
12
Lake Mary, FL
We are new to owning a pool & are attempting to service it ourselves rather than get a monthly service. For the 1st 6 wks after pool was complete, our builder provided complimentary pool service from a reputable pool company to get our water balanced. We also got our own test kit to get used to doing it & understand water chemistry better. During those 6 wks, our results were always within range per what the kit said it should be. However, now that we're on our own we can't seem to keep FC or TA up, & PH is constantly on the high side. We don't know if it's the test kit that's not working right, the reagents, or what! The pool service company was using chlorine tablets in our inline chlorinator, but we are attempting to just use liquid chlorine. (We're not opposed to using tablets, but prefer not to have other things introduced into the water along with the tablets). We took a sample to our local pool store & their results were quite different from ours... especially TA.

This morning's results from our kit were:
FC - 2.7
TC - 2.7
TA - 50
PH - 8.0
CH - 502 (fyi, we're in a very hard water area)
CYA - 55

Pool store results 2 hrs after we did our own test:
FC - 1.5
TC - 1.5
TA - 120
PH - 7.8
CH - 400
CYA - 54

And, we tested again near end of day after kids finished splashing around:

FC - 0.5
TC - 0.87
TA - 55
PH - 8.4
CH - 415
CYA - 54

Our TA would fluctuate from 27-50 on any given test. The kit says 80-100 is in range, so here we are adding pounds of baking soda (going according to pool math) multiple times per week, only to retest the next day & it only goes up by 10-15. Meanwhile, the PH of course is going up.

So, according to the store's results, we need to be adding acid to decrease TA & PH. How can we trust our test results? Here we are trying to increase TA when we actually should've been decreasing it! Could it be the digital kit itself? Bad reagents? User error? Also, the pool store says to add slightly less than 2 cups of acid, but pool math says 3.5 cups (we entered the pool store's results to see if the recommended amount was the same). We made sure the correct type/ strength was chosen in the drop-down.

My brain hurts after all this! Not sure if we need to get a different test kit? We have two colorblind people in the house, so we pretty much have to have a digital kit.

Thanks!
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
29,881
Laughlin, NV
Welcome to the forum!
We only look at pool owner test results. The ColorQ is not one of our preferred test kits, but it typically provides OK data within its limitations excluding CH. See Pool Test Kits - Further Reading

You need to add chlorine. Your CYA is 60 ppm so follow the FC/CYA Chart for that CYA. You do need to add chlorine every day to replenish what is lost.
pH could be lowered to 7.6. Your last test of 8.4 pH seems rather high.
I suggest you read ABC's of Pool Water Chemistry.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
29,881
Laughlin, NV
As far as being color blind and kits, the TF100 that is the preferred kit uses color changes except for pH. And you can get a pH meter.
Can you tell pink to clear, green to red, and red to blue?
 

kikipunx

Member
May 9, 2020
12
Lake Mary, FL
The green to red could be difficult since they are red/green colorblind. It depends on the shade. But I do plan on getting a different test kit. Probably the K2006 or K2006C.

Another question... should we try to get our alkalinity in range before adjusting pH? Vice-versa? Or does it matter? My pool math is telling me the amount of baking soda I need to use to increase my alkalinity from about 56 (current result) to 80. But my pH is already at 8.3 today and that has to get lowered which the baking soda would do the opposite of. Is the alkalinity at 56 an okay amount? Pool math says the range should be 50 to 90.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
29,881
Laughlin, NV
It is a conundrum to have low TA and high pH. I question the test result of one or both.

If true, add 20 ppm TA worth of baking soda. That will not effect pH much. Then lower your pH to 7.6.
 

kikipunx

Member
May 9, 2020
12
Lake Mary, FL
I question the TA results myself. Especially after yesterday's trip to the pool store. I know the forums only use the owner's results, but when my result was 45 & the store's was 120.... that's too much of a difference!

Thanks for your input!
 

DeanP66

Well-known member
Mar 26, 2014
798
San Jose, CA
Test again with either your TF-100 or Taylor K2006C kit when you get it. I'll bet with pH that high, that TA # is off. I bet you're more in line with the pool store's TA #.
 

Saturn94

Well-known member
Mar 11, 2015
910
SE Virginia
The green to red could be difficult since they are red/green colorblind. It depends on the shade. But I do plan on getting a different test kit. Probably the K2006 or K2006C.

Another question... should we try to get our alkalinity in range before adjusting pH? Vice-versa? Or does it matter? My pool math is telling me the amount of baking soda I need to use to increase my alkalinity from about 56 (current result) to 80. But my pH is already at 8.3 today and that has to get lowered which the baking soda would do the opposite of. Is the alkalinity at 56 an okay amount? Pool math says the range should be 50 to 90.
I have ”color blindness” (a misnomer). I don’t have any trouble with the TA test (green to red). I do ok with the pH test as well.

I do have trouble with the calcium hardness test (red to blue). The initial red looks purple to me and can‘t tell the point at which it turns blue. I just watched a Taylor video demonstrating this test, and despite them saying it starts out red, it still looks purple to me on the video, and again can’t see the transition point to blue.

I think you’ll have try the Taylor/TF100 test yourself to see if you have any issues.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
29,881
Laughlin, NV
If you have a vinyl liner pool and you know your fill water CH is low (under 100), and you do not have to add a lot of fill water due to evaporation, you can just not test CH. It does not come into play with any other parameter under those conditions.
 

Saturn94

Well-known member
Mar 11, 2015
910
SE Virginia
If you have a vinyl liner pool and you know your fill water CH is low (under 100), and you do not have to add a lot of fill water due to evaporation, you can just not test CH. It does not come into play with any other parameter under those conditions.
?Yes, I gave up on the calcium test many years ago when I learned it wasn’t important for our vinyl lined pool and learned our city water is low in calcium.

Ben at PF did tell me about an alternate way to do the calcium test that does help some (involves increasing color satuation and two sample tubes for comparison). I don’t want to derail this thread any further, so if anyone wants to know the details just send me a PM (I don’t know if TFP would want me to post it?).
 

kikipunx

Member
May 9, 2020
12
Lake Mary, FL
I did what was suggested & added enough baking soda to raise TA by 20. Then added acid to bring PH down according to pool math calculations. But, when I re-tested the PH it only went down 0.1.

Then, today's test results were:
FC - 4.3
CC - 0
PH - 8.2
TA - 52
CYA - 61 (not sure how it went up by 7 in 1 day when I didn't put anything in that would raise it?)

So, I left TA alone, since I don't trust those results anymore. But based on that low #, pool math said to add only 6 oz of acid to bring PH down to 7.6. Did that, let circulate 4 hrs, re- tested, & it didn't budge. Another indication the TA is probably higher than my results.

The FC results & pool math calculations to raise it are spot on, so that's good at least!

Any recommendations on how to know how much acid to put in with unreliable TA results, until our new test kit comes in? We can't order it until Friday, so won't get until the following week.
 

IceShadow

Gold Supporter
TFP Guide
Jun 8, 2019
2,177
Milwaukee, WI
What are you using for acid? We recommend Muriatic Acid - if you’re using dry acid you could get sulfates building up in the water.

I’m very concerned about giving advice until your kit is in. I’d recommend riding it out and waiting on the kit, but maybe someone has better advice.
 

kikipunx

Member
May 9, 2020
12
Lake Mary, FL
I finally got my TF100 kit today. It's a bit intimidating after getting used to the LaMotte! I did splurge for the speed stir. So, LaMotte is still giving me TA readings of 42-50. Pool store still telling me 120. With how hard it has been getting my PH down, I'm siding with pool store results!

There are a couple results that just seem way too high.

My readings from TF100:
FC - 4
CC - 0
PH - 7.9 (finally getting it down! )
TA - 220?!
CH - 1225?!
CYA - 55

On the TA test, do I keep adding drops until it's red, or is pink ok? It turned clear at 20 drops, pink at 22. I kept adding drops thinking I needed to see red, but I stopped at 30 drops because it wasn't getting any darker. I did the test twice to make sure & got same result both times.

On the CH test, it didn't turn blue until 49 drops! I tested our regular tap water...35 drops. So, does that mean the CH of our regular water is 875? No way to reduce CH to be within range?

Based on those results pool math is telling me to add a little over a quart of acid to bring PH down to 7.2, reducing TA in process. Then aerate to bring PH back up in range.

Thoughts?
 

kikipunx

Member
May 9, 2020
12
Lake Mary, FL
Great tips... I'll try those methods tomorrow. I did wipe the tip of the bottle after each drop when doing TA, but wasn't holding bottle vertically- more horizontal instead. I'll keep you posted on tomorrow's results.
 

IceShadow

Gold Supporter
TFP Guide
Jun 8, 2019
2,177
Milwaukee, WI
Even if the TA is that high - the only reason to push it down with acid/aeration is to get your CSI in check if it’s too positive. Which if your CH is really 1200+ it may be. I would think if that’s the case you’d want to exchange some water. Test your fill water for TA / pH / CH when you can.