Automatic pH controllers

Problems relating to pH and total alkalinity.
Increase ph, increase TA. Reduce pH, reduce TA.
pH chemistry advice and techniques for the pool.
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Automatic pH controllers

Postby osmosis » Tue 19 Sep, 2006 00:47


I would be really interested if someone can provide me with some feedback with regard to automated pH controllers, such as the Zodiaz pH Easy. Do you think these are worth the money?

I'm trying to make my pool care a little easier.

Any feedback would be appreciated.

Many thanks.


Re: Automatic pH controllers

Postby Guest » Tue 19 Sep, 2006 14:42

osmosis wrote:Hi

I would be really interested if someone can provide me with some feedback with regard to automated pH controllers, such as the Zodiaz pH Easy. Do you think these are worth the money?

I'm trying to make my pool care a little easier.

Any feedback would be appreciated.

Many thanks.

Usually the pH does not fluctuate enough to justify spending money on automation. It takes but a few minutes to read and correct the pH anyways. I don't know if the system you mention has a temperature probe but if you're going to be spending money I would ask for a temperature-compensated unit.

You may also want to investigate the replacement costs of the pH probe, they need replacing after a few years. And ask about calibrating the unit, that too may be much more of a hassle than using phenol red.

IMHO it's not worth the money.

Automatic pH controllers

Postby Guest » Mon 16 Mar, 2009 05:50

Be carefull I bought a Ph controller from Zodiac, use the chemical recomended by their distributor after 4 month it broke, they sent it back and still did not work, then said that I used the wrong liquid and gave me a repair esimate 30% more the the value of a new on. The electrics failed which did not have anything to do with the liqiud. Took them 6 months to get to the point where I told them where to put their unit.

Automatic pH controllers

Postby flagpools » Mon 16 Mar, 2009 07:17

Usually the pH does not fluctuate enough to justify spending money on automation. It takes but a few minutes to read and correct the pH anyways.

I agree 1,000% :wink:

More automation means more maintenance and more to go wrong. I have to add chlorine, so I can add the acid at the same time (5 minutes earlier to be precise).

If the whole pool is automated then staying away from it for too long could spell disaster. A few minutes once or twice each week is not too much to ensure pool water balance and water hygiene.

Just my 2 cents worth :)

Automatic pH controllers

Postby Poolsmith » Fri 20 Mar, 2009 12:42

A suggestion - you might want to explore using CO2.

I have been servicing about 20 CO2 pools in the Phoenix Metro area for almost 6 years. At first, I didn't understand the process so I turned the systems off and reverted to liquid acid. However, the acid process was so onerous that I decided to revisit the CO2 process.

Through many hours of research, I learned that the CO2 method was viable and it was overwhelmingly preferred by commercial pool operators worldwide. Through hours of observation, I learned that CO2 was safe and easy to use as long as the delivery system was functioning properly.

Most of the time (as long as there is CO2 in the cylinder), my weekly process is to test the pH and enter the result in my log. Typically, the readings do not vary more than .1 of a point pH, week to week. If there is a variation of more than .2, I do some troubleshooting. I have been documenting this process for almost 5 years. The data is compelling.

As a result, we invented a process and an injector. We recently received notification that our process, Carbon Dioxide InpHusion, has been granted patent protection.

Our process does not utilize pH sensors because of the maintenance problems. I found that it required too much effort to monitor the performance of the sensor. Instead, we developed a process that uses a time and volume formula. In reviewing 4 years of data, we discovered a similar CO2 demand formula for about 20 different bodies of water. We programmed that formula into a PCB and developed a delivery system that works on virtually any residential pool. We currently have systems operating in Costa Rica, Puerto Rico, California, Texas, Louisiana, Georgia, Massachusetts, Hawaii, and Arizona.

If you have any interest I welcome your inquiries. Also, you can check out our website at

Poolsmith Technologies LLC
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Automatic pH controllers

Postby chem geek » Fri 20 Mar, 2009 18:22

If you are manually dosing the pool with chlorinating liquid or bleach, then lowering the TA sufficiently will make the pH much more stable. With an SWG pool, this also helps a lot as does the use of 50 ppm Borates, but there is still a tendency for the pH to rise in SWG pools. If you use a pool cover, you can also get very stable pH. This is the case in my own 16,000 gallon pool where I have around 1 ppm FC per day chlorine demand and only use 12.5% chlorinating liquid about twice a week and have fairly stable pH only adding a couple of cups of acid about once a month or so. Total cost: around $15 per month.

If the primary source of rise of pH in pools is the outgassing of carbon dioxide, then lowering the TA level is the easiest way to reduce that since the cause if from pools being intentionally over-carbonated (TA mostly measures the amount of bicarbonate in the water). Though one can certainly use carbon dioxide injection to offset the carbon dioxide loss, simply lowering the TA can let one avoid the regular pH adjustment in the first place.

The 50 ppm Borates act as an additional pH buffer so having a lower TA (and perhaps raising the CH if the pool is plaster so that the saturation index remains near zero) helps reduce the rate of pH rise. Also, the Borates are a mild algaecide so lower chlorine usage in some pools and in SWG pools this can let one turn down the SWG ontime. Also, for SWG pools that are outdoors and exposed to direct sunlight, using a higher CYA level of around 80 ppm can lower losses due to sunlight (especially in low-bather load pool such as most residential pools) and this also lets one lower SWG ontime. With lower SWG ontime, there is less of a pH rise (possibly from chlorine gas outgassing, if undissolved; also less bubbles creating aeration that increases carbon dioxide outgassing).


Automatic pH controllers

Postby Guest » Sat 21 Mar, 2009 01:38

you can check out our website

I did and was disappointed. There is no real information there.
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Automatic pH controllers

Postby Rosco59 » Thu 26 Mar, 2009 16:12

PH controllers are scientific instruments that require a lot of care .
In a commercial pool where outside specialist contractors come in every 3 months to clean and recalibrate they are probably fine.
But for the average residential pool owner simple technologies like POOLSMITH,S carbon dioxide doser makes sense.
No probes and a predictive measure of a non toxic gas instead of hazardous acids that if incorrectly handled or mistakenly overdosed by man or machine can damage your coping or pool surface.
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Automatic pH controllers

Postby Me... » Fri 27 Mar, 2009 21:39

Automate both the chlorine and the pH to keep things easy. But, you must still keep the other chemical levels maintained or things can go crazy on you once you automate. I see it where once people put controllers on they seem to forget about alkalinity and calcium and CYA if its an outdoor pool. Spas are typically harder because they are smaller much more volatile bodies of water. This requires a more careful look at feed rates and solution strength and might warrant a more programmable controller. Then again residential spas normally don't get the high bather loads that can drive a controller nuts.

Very important is to remember that you need to manually balance both the water chemistry and temperature and then calibrate and setup the controller. A flowcell is a really great idea because it helps maintain a regular flow over the probe. And the probe may need to be in the water for a day to completely adjust and be ready for calibration.

So while it is an expense, so is Air Conditioning and Microwaves and everything else we spend money on to make certain things easier. A 2k system on a 500 dollar aboveground, not. But a 2k or even 5k system on a 30k or more pool seems to start making sense.

Automatic pH controllers

Postby disgusted » Tue 17 Nov, 2009 13:30

I bought a Zodiac controller, after 6 months ,it stoped working. I sent it back under quaranttee and they refuse to replace the sensor as I is not under quaranttee,it should be replaced after every 12 months. I bought a new one but the unit still did not work. I sent the whole unit back and because I did not use their recomended acid they would not repair unit under quaranttee.(The acid only touches the plastic tubes and the plastic pump, the problem was with the electronic board) The quote they gave me for repair was just a little more than I had paid for the unit. The suppier where I bought it told me that the after sales service was so bad he no longer sells Zodiac.

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