Electronic PH Meter

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Catanzaro

Catanzaro

Platinum Supporter
TFP Guide
Jul 30, 2014
3,508
Monmouth County, New Jersey
Can someone recommend an Electronic PH Meter?

Here are some of the ones that I have seen on line. I am having a difficult time with the colors, etc. May be worth spending the $$$.

HI98103 Checker® pH Tester
AquaChek Tru Test Digital Reader

Attached below is the link on "google". Thank you.

Google

Unless there is a drop based test that I can purchase, which I prefer.
 
Unfortunately we don't know of a "count the drops" based test, though you can use the acid and base demand reagents in some Taylor kits to move the pH and and down in the pH test if the issue is that you are just unsure if it's at a particular color, but you can still see colors. If you can't distinguish the colors much at all, then a meter may be your best option (if there isn't anyone else who can help you with that test), but with meters you need to keep their membranes wet and should calibrate them and check them against reference solutions fairly regularly.

I don't think enough people on this forum have used enough of these meters to be definitive. The Amazon ratings might be a better thing to look at, especially the user comments. Unfortunately they seem to show that more than 20% of users for the two you listed find the meters worthless and inaccurate. This one has better ratings, but you need to replace the probe annually and that costs. This one has fewer negative ratings than the ones you are looking at but still has negative ratings. Basically, these meters are finicky and some may work while others do not, even for the same model and manufacturer. Note that buying some of these from Amazon does not provide warranty from the manufacturer so you may be better off buying direct or from a channel that supports the manufacturer's warranty.

Hach generally makes good instruments, but their units on Amazon aren't rated. Ones without replaceable sensors run around $70 and have 0.1 accuracy and resolution while those with replaceable sensors run around $115 but are more accurate (0.02 accuracy with 0.01 resolution).

Look at a TFP Google search of electronic pH meter for some more info/reviews though most are older/dated.
 
Thank you Chem-Geek:

I actually added a little bit of acid this morning, (a few ounces of dry acid), and then added a few more based on the calculator. It appears that the color has changed and now I can see the difference. I am hovering at around the 7.8 range and was probably around the 8.2 range with the Taylor Kit. Tomorrow morning, I will do all the testing to make sure that the PH had adjusted accordingly with the second addition, which I tested about 2.5 hours later. The turnover rate is pretty quick and I would not be surprised if that is where I am. There will be more acid added in a few days to bring the PH down to around 7.6. It appears my PH has been increasing through the year. I have four (360 degree-rotating heads that create a lot of water movement) in the water, with a total of 8 returns, with no waterfall or spa's, etc.

I also added dry acid a few weeks ago and the TA lowered by 20 from 140 to 120.

Here is where I am as of last Saturday's morning testing:

CYA 50
TA 120
CH 200
FC 7 (which drops to about 4 each day) Extended test kit each Saturday. I will be testing 2X weekly as sometimes I do not burn off as much FC as projected and will be adjusting the additions in the middle of the week, and/or possibly skipping a day.
CC 0
TC 7

My water is crystal clear (Thanks to TFP). :)

I have added Borax once to raise Alkalinity and Dry Acid twice to lower PH. The first time was a few ounces (very little) compared to today. I followed the instructions on the Chlorox PH Reducer that was purchased at Lowes. Next time, muriatic acid as they had none in stock when I was at Lowes. Brush weekly and there has been no signs of algae. No one has complained about any burning of eyes.

Question: Is this normal for my pool to have the PH increase slowly over time. I started at 7.2 and added 40 oz. of Borax only once. The PH adjusted very quickly to around 7.6-7.8. I have read that the liquid chlorine with the salt and lye by-product could be part of this. Any thoughts?
 
Just a comment.

Borax does not raise alkalinity (not by much at least). It is used to raise pH WITHOUT raising alkalinity.

Alkalinity is raised with baking soda which has negligible affect on pH.

To raise pH and Alkalinity, you use washing soda or soda ash.


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Also, be judicious in your use of dry acids. It adds sulfates to your water. Since your pool is vinyl and you don't have an SWG, sulfates are not as bad. Muriatic acid is better although most folks don't like the smell of the fumes sometimes. Check for any independent pool stores in your area. We have one here in Tucson called e-Konomy Pools and I can get MA in a 4-by container that is four refillable 1-gallon jugs and the cost is $4.75 per gallon with a one time, refundable $6 deposit for the safety carrier. I use MA frequently so it's nice to have a cheap source and not discard lots of empty plastic. They do the same for 12.5% LC but I don't use a lot of LC. to justify four gallons. It would degrade to much before using it all.

Just some random thoughts...


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The primary source of pH rise in most pools is due to the fact that they are intentionally over-carbonated. TA is mostly a measure of the bicarbonate in the water. That is in equilibrium with carbon dioxide and is at a higher concentration than when in equilibrium with air. So carbon dioxide outgases from the pool and when this happens the pH rises (with no change in TA).

You can reduce the amount of pH rise in your pool by not adding chemicals to raise the TA. Instead, when you add acid over time to lower the pH, your TA may drop, so let it do so at least down to around 70 ppm or wherever above that you find that the pH is more stable. There is a process for accelerating this if you want to get their faster by adding acid at low pH and aerating as described in the Pool School article Lower Total Alkalinity. Up to you if you want to lower your TA quickly or just over time as you add acid, but do not add Alkalinity Up (baking soda, sodium bicarbonate) or pH Up (washing soda, sodium carbonate) after you've added acid or you will just be on a merry-go-round of frustration.

Though there is some excess lye in chlorinating liquid and bleach, the amount is negligible and usually not noticeable in the chlorine usage amounts for residential pools (commercial/public pools notice it more because they have much higher bather loads).
 
Fully understood ! Thank you.

Questions:

Assuming I have to raise the PH or TA, should I be using the other alternatives, i.e. Borax for PH (or just aeration), and what about TA? Or are you stating, leave the TA as is?

Is there a certain amount of time that you can use the other chemicals, say 1 week or longer after adding dry acid, so I will not be on the merry-go-round?

Should I give the dry acid away and purchase straight muriatic acid?
 
Your TA is already high if anything because by definition if your pH is rising your TA is probably too high especially if it's higher than our normal ranges. 120 ppm TA will outgas carbon dioxide and have the pH rise a lot faster than a TA of 80 ppm. This is especially true if you have aeration sources (waterfalls, spillovers, fountains) but it also happens more slowly without such features.
 
Over the last few weeks, I have been slowly lowering my PH to lower the TA. I finally have the TA at around 100. Each time the PH has increased to 7.8, I bring it down to 7.5 and then 7.2 (somewhere around there). The strange part is that after 7.2 in the morning, the PH quickly, within a few hours jumped to 7.5. It seems to like this PH level. For now, I will leave as is over the next to make sure it does not keep increasing. Then I will reduce again to 7.5 to lower the TA.

Question: Can PH change that quickly over 2-3 hours? I have been checking daily to make sure levels stay within the ranges.

Additionally, have 2 water sources. The well water and the house water. I will be performing testing on both to determine PH, Alkalinity, Calcium, etc. We have had a lot of rain so I have not had to add water for a while. Now that the heat is on in NJ, in a few days, I may have to fill the pool. There are no leaks and this is due to evaporation.
 

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pH rise is primarily controlled by the rate of CO2 out gassing from the water. I won't go into the chemistry but basically as bicarbonate is converted to dissolved CO2 gas, hydrogen is consumed and pH increases. The rate at which CO2 outgasses from water is, in part, proportional to the concentration of CO2 in the water. At a pH of 7.0, the amount of CO2 is double what it is at a pH of 7.6 and so the rate at which CO2 out gasses is higher. Thus the pH rises more quickly.

This why folks that have a high TA and lots of aeration should try not to get too stuck in keeping their pH low, otherwise they always fight with a fast rising pH.


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Catanzaro said:
I am having a difficult time with the colors, etc.
...
Unless there is a drop based test that I can purchase, which I prefer.
Click to expand...

I know what you mean. The kit I got from the PB was tough to determine colors. The reagent (which I assume you are referring to when you say "drop-based") kit (Taylor K-1000 - TFTestkits.net) that comes with the TF-100 was MUCH better (even though it looked the same).

I bought one of the electronic test sticks (the yellow and black one) under the recommendation of the PB...but you have to calibrate it every few months and that was a pain for me. I can send you mine if you want it but you'll have to purchase your own calibration solution packets.
 
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