Lamotte v. Taylor.

Bwdonohues58

Gold Supporter
In The Industry
Apr 22, 2019
47
Homer, AK
OK, so I bought the Lamotte #2086 Color Q Pro about a year ago but my pool wasn't finished until mi-June, 2020. At that time I bought all new chemicals for it. The color Q gave me very inaccurate readings for CH and I ended up putting in way too much Calcium chloride. So I bought a Taylor K-2005 about a month ago. The Taylor kit is very good for CH and TA due to the rather abrupt color change drop by drop. I have been draining off water and replacing it with fresh to lower CH. This morning I measured the TA on both setups. Taylor gives 60 and Color Q gives 48 (what's up with that?). On CH, Taylor gives 230 while Color Q gives 138 (hello?) I am quite sure that Taylor is correct on both of these. However, I find that trying to match up the pink colors for free chlorine on the Taylor setup is hopeless, at least for me. Actually, they all look the same to me (pink!). The same goes for the PH. I replaced about 1,000 gallons of water yesterday and refilled it to full with the hose, I got a PH of 8.2 on the Lamotte and 7.8 on a Safe Dip unit a friend loaned to me. This is a pool of 10,300 gallons. So I added about 10 ounces of muriatic acid, diluted in a 5-gallon bucket, and let it run for 12 hours. Now the Lamotte shows a Ph of 7.5 and the Safe dip shows 7.7. I realize that this is really no big difference, but it does have a great effect on how effective the free chlorine is in the pool, and I want to know the real deal (is that so wrong?). I add chlorine every day using a Stenner pump so I really don't have to worry about getting the right FC level because I know how much chlorine the pool uses every day and I just add that every day with the Stenner. The PH is a whole nutha thing, however. I want to keep it at 7.6, period. OK, enough said, so here's my question: Does anybody know of a simple, accurate device that I can use to get the true PH? The readings I'm getting are all over the barn!
 

HermanTX

Gold Supporter
May 20, 2020
771
Katy TX
Well, as they say, a man with 2 watches really never knows what time it is. Seriously, I think you find on the forum that the Lamotte tester has its limitations. I would trust the Taylor kit assuming the reagents are still within their expiration date limit. Have you tested your fill water? Could that be driving some of the changes in your testing? You can purchase a $100-300 electronic pH tester but you need to keep it in calibration so that can be challenging as well.
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
19,403
Bedford, TX
58.

pH has very little effect on how well your FC (chlorine) works.. unless you have very little FC in your pool...

Obviously, it is your pool and you can do whatever you want, but trying to keep your pH at 7.6, "period" is just a lot of fuss about nothing...

I use both the Color Q and my TF-100 and find that the Color Q does a pretty good job of testing pH, but as you have found out, it does a poor job on CH, mainly because it actually measures Total Alkalinity (TH) and not CH... I know it says CH, but if you ask LaMotte they will tell you they test for TH... Depends on your local water as to how close CH and TH are..

Thanks,

Jim R.
 

Oly

Gold Supporter
Jun 28, 2017
1,676
Fresno, CA
So I bought a Taylor K-2005 about a month ago. However, I find that trying to match up the pink colors for free chlorine on the Taylor setup is hopeless, at least for me. Actually, they all look the same to me (pink!).
This is why TFP recommends the K-2006c or the TF 100 test kit because the FAS DPD test is a titration test for Free Chlorine FC and utilizes a color end point like the CH and TA. You can add the FAS DPD test to your kit.
Keep your pH below 8 don't drive yourself nuts, but do pay close attention to you CSI calcium saturation index assuming you have a plaster pool and let that guide your pH and TA targets. Test your tap water and anticipate how it changes your water chemistry when topping off your pool.
 

Dirk

Gold Supporter
TFP Guide
Nov 12, 2017
7,118
Central California
Simplify... Add the Taylor FAS-DPD test and stop using the "pinkie" FC test, ditch the Q (OK, well, put it away for a while and just use the Taylor, see how that goes). You're trying to get your money's worth out of the Q, at the expense of your mello! You already own a perfectly fine pH tester. Try using 4 drops instead of 5 for the Taylor pH test. It will change your life! ;)

Stop wrestling with pH (it will always win). Keep an eye on your CSI and see if you can maintain a good number while letting your pH live where it wants to (about 7.8 works for me). When I did that, my acid use went way down and my TA took care of itself.
 
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Bwdonohues58

Gold Supporter
In The Industry
Apr 22, 2019
47
Homer, AK
OK, I get it. But here’s the chart I saw in Sunplay:


% Active HOCI (Hypochlorous Acid) pH
97 %6.0
91 %6.5
76 %7.0
66 %7.2
50 %7.5
33 %7.8
24 %8.0
9 %8.5
*Chart is from the National Swimming Pool Foundation's Pool and Spa Operator Handbook.
 

Wobblerlorri

Bronze Supporter
I got this pH meter when my husband had to pitch in on testing when I broke my ankle this season (still all casted up, didn't get to swim all season!)


I know it's cheap, but it has over 1000 reviews and a 5 star rating. I used a similar meter in the lab. As long as you keep it calibrated, it will give you accurate readings. Way better than that color matcher!
 

mgtfp

Bronze Supporter
Mar 5, 2020
468
Melbourne, Australia
OK, I get it. But here’s the chart I saw in Sunplay:


% Active HOCI (Hypochlorous Acid)pH
97 %6.0
91 %6.5
76 %7.0
66 %7.2
50 %7.5
33 %7.8
24 %8.0
9 %8.5
*Chart is from the National Swimming Pool Foundation's Pool and Spa Operator Handbook.
That table applies to pools without CYA. With CYA, the HOCl-concentration is much less dependant from pH. As long as you stick to TFP's FC/CYA chart, you don't have to worry about pH making your FC inefficient.
 
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Leebo

Admin
TFP Expert
LifeTime Supporter
Jul 21, 2011
10,066
Eastern Ohio
OK, I get it. But here’s the chart I saw in Sunplay:


% Active HOCI (Hypochlorous Acid)pH
97 %6.0
91 %6.5
76 %7.0
66 %7.2
50 %7.5
33 %7.8
24 %8.0
9 %8.5
*Chart is from the National Swimming Pool Foundation's Pool and Spa Operator Handbook.
What you are shown here is totally accurate, but misleading at the same time. pH does in fact play a major part in the amount of active HOCL............when there's NO CYA in the water. Add CYA and you're golden. Take a quick look first at the following video and then take a read in some advanced parts of TFP's Wiki to help further understand the concept.

 
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Bwdonohues58

Gold Supporter
In The Industry
Apr 22, 2019
47
Homer, AK
This is why not:


The Relationship of pH, Chlorine, and Cyanuric Acid Levels


If your pH goes down, the effectiveness of your chlorine goes up. This is commonly understood. But in the presence of cyanuric acid, the relationship between pH and chlorine is substantially altered. For example, if your pool maintains a pH of 7.2, about 63 percent of the chlorine is in its active form. If you introduce just 30 ppm of cyanuric acid to the pool, this drops to 1.6 percent of the chlorine being in its active form.
 

Bwdonohues58

Gold Supporter
In The Industry
Apr 22, 2019
47
Homer, AK
I see you’re currently “In the Industry.” Is this a public or private pool?
Interesting question. I fully assumed it would be public and require Alaska DEC certification but I called and was informed that a Physical Therapy pool was considered private. However, I have downloaded all the a State regs and printed them out. I try my best to comply with the spirit and the letter of all regs. I have monthly coliform and E. coli tests run at the State-approved labs and they have all come back squeaky clean. We usually only have 2 clients and 2 therapists in the pool at any one time, but this is because of COVID 19. Right now I am running with 1.5 ppm FC, 7.5 PH, 60 TA, 230 CH. No salt, no CYA, or any other chemicals. 10,300 gallons. The room has no windows. The pool consumes about 10-11 ounces of 12.5 % bleach per day. A bit less on weekends. I just switched to muriatic acid from dry acid on advice from TFP. I think I will have to put in about 8-10 ounces of MA per week to keep it at PH 7.5 but have to see. I will do whatever it takes to keep it at 7.5 PH and 1-1.5 FC. I also have a UV (Spectralight) and an AOP (Clear Comfort) that do the heavy lifting as far as bacteria/virus killing goes. People love this pool because there’s no smell and their skin feels nice and smooth when they get out. Water is always crystal clear. 16’ by 26’