Automation for pH control

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Dirk said:
A very simple DIY wiring hack will prevent the issue but would void the warranty
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Has anyone looked for or located replacement connectors? I'm thinking your hack from Post in thread 'Hacking IntellipH to work in cold water' Hacking IntellipH to work in cold water
But using a male and female connector so that the modifications to wiring is effectively done on a jumper which could be done pre warranty expiration.
 
Ahultin said:
Has anyone looked for or located replacement connectors? I'm thinking your hack from Post in thread 'Hacking IntellipH to work in cold water' Hacking IntellipH to work in cold water
But using a male and female connector so that the modifications to wiring is effectively done on a jumper which could be done pre warranty expiration.
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Not quite sure what you're describing. The factory four-conductor connector inside the IntellipH is under-spec'd. It fails to handle the current under certain conditions. That's the weak link. Any modification to address that: replacing the connector, removing it and soldering directly to the board (the fix I used) or bypassing the connector ahead of it (the fix I now recommend) might void the warranty should a Pentair tech catch it.

The drawings I submitted in the thread you reference is one way to do the bypass. It's how I would do it, because I trust soldering over mechanical connections. But one could use Wago connectors to the same result, or even just wire nuts. Any way the bypass is established will solve the problem. But any such modification could void the warranty.
 
Oh, I just got it. You're talking about leaving all the original wiring alone, and finding a set of male and female connectors that mate to the existing connectors. Then apply the bypass to the wires between those two additional connectors. This jumper could then be easily removed in advance of a warranty service call, and none's the wiser. Yes, that is an interesting idea. It would just be a matter of finding the connectors.

But that might not solve the problem. Probably wouldn't, in fact. The real weak link are the pins inside the factory connectors. My theory is that they are of inferior metal, that corrode slightly, or don't connect all that well, or both, and resistance builds up on the pins, which starts to heat up and exacerbates the corrosion to the point of them melting and failing. Something like that.

Your jumper idea would still leave those original pins in the mix, still subject to the over-current. The bypass has to happen before the pins, such that the excessive current never gets to those pins. And the only way I can think to do that is to splice the existing wires, before they enter the factory connector. So that puts you back into voiding the warranty.
 
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Dirk said:
Stuck with me from junior high chemistry class: "Acid inta wahtah, 'cause that's the way ya aughta."

@cpachris, the type of acid dosing system that might be best for you might be dependent on your existing (or planned) equipment (SWGs, automation controllers, timers, etc). If you could fill in your signature, you'll get better advice. Something like mine is ideal.
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@Dirk Rhyme committed to memory....and filling in signature on my to-do list. :p

I'll mention briefly that all my equipment is Hayward right now, if that helps with recommendations. SWG, Heater/Chiller, Pump(s) and DE filter. some other lighting/features tied into the Omni hub also. And I do have the Chem Sense with the pH and ORP probes. They are not controlling anything...but the pH is usually within 0.1 of my taylor test drops. So I think it's pretty accurate so far.
 
cpachris said:
I'll mention briefly that all my equipment is Hayward right now, if that helps with recommendations. SWG, Heater/Chiller, Pump(s) and DE filter. some other lighting/features tied into the Omni hub also. And I do have the Chem Sense with the pH and ORP probes. They are not controlling anything...but the pH is usually within 0.1 of my taylor test drops. So I think it's pretty accurate so far.
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A Pentair IntellipH is dependent on the installation of a Pentair IntelliChlor, and "from the factory" cannot work stand-alone. You'd have to do some hacking to get an IntellipH to work by itself. (Which we can show you how to do.) But several of the nicest features of the IpH are the ones that work in harmony with the IC. I could argue that the IpH, even on it's own, is a great solution, just not as good as the IpH/IC combo. As you review other systems, look for some of these niceties:

I really like the way the IpH tank is designed.
- It is air/acid fume tight, and has a way to vent its acid fumes away from your equipment pad
- It's got a great solution for adding acid: it's mouth accommodates an entire 1 gal acid jug, you place the sealed jug in the mouth and it punctures the seal as you lower it in. You can "dump and run" and stay away from acid fumes while the jug "glug-glugs" into the tank.
- The pump is built into the tank, so no separate things or tubes bolted to your wall.
- The pump is manufactured by Stenner
- The tank is a good size, about four gallons. You can buy very large acid tanks, 15 gals +, but would you want to? A pump/timer malfunction could empty the entire tank into the pool. Personally, I don't load more than about 1.5 gals of 31% acid into mine (which I then dilute 1:1 with water). So a major malfunction won't be a serious chemical accident in my pool.
- The tank has a wide base that can be bolted to the pad.
- The tank is semi-transparent so you can keep an eye on the level

With the Pentair IC in the mix, the combo has great safety features:
- the IpH controller limits the amount of acid it will pump each hour
- the IpH adds acid hourly, so that your pH stays very stable all day, every day. You don't get a big dump of acid once a day, or once a week
- the IpH controller can monitor and control the IC, and can regulate the IC's dispensing in 1% increments
- the IpH monitors the IC's temperature and flow sensors, and so will not pump acid under the wrong conidtions
- the IpH shuts down the IC while the IpH is dispensing acid, so you don't get a dangerous mix of acid and chlorine at the same time in your pipes
- the IpH controller offers very easy acid dispensing adjustments in 1% increments

If you add an acid injection system, you need to figure out how to add some of the safeguards that are built in to the IpH/IC combo:
- you can't allow a timer to pump acid while your SWG is producing chlorine, and
- you can't allow a timer to pump acid unless water is flowing in the plumbing, and
- you need to limit the amount of acid pumped at any one time in case of a timer or pump failure.

You can run a simple timer/pump acid system without these safeguards, but I strongly recommend against doing that.

That's the short version... ;)
 
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tloomos said:
Can you explain this one? Why can't acid be added while the SWG is generating chlorine?
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Because chlorine and muriatic acid combine to make a toxic gas (sorry, I forget which), and it is quite harmful to humans. It's why we always recommend you add liquid chlorine and acid at least 15 minutes apart in the main body of your pool while circulating the water the whole time.

Also, and @JoyfulNoise can fill in the details, I seem to recall that flowing a high concentrate of low pH water over the SWG's plates while the electrolysis is going on is bad. Not quite "cross the streams bad," but bad for the delicate plates.

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The IntellipH handles these issues automatically. For those assembling another sort of acid injection system, they would have to schedule the acid dosing around the SWG runtime. Which means you can't really have the acid going in each hour (like an IntellipH dispenses it), because you'd have to de-power the SWG each time, and then it would have to go through it's startup sequence that many times a day. You'd have to dump in acid just before the SWG starts up, or right after, and also coordinate the main pump to be on while dispensing acid, but in a mode that does not also engage the SWG. It can be done, it's just something to be aware of.

But it's somewhat complicated by the potential problem of the timer running the pump and the timer running the SWG and the timer running the acid pump getting out of sync. This is easy to avoid when a pool automation system is in the mix, but if you run three different independent timers, you have to safeguard this issue somehow.

These and other reasons is why I like the IC/IpH combo, because Pentair figured all this out for me.
 
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MyAZPool said:
If that's the "Readers Digest" version, where in the Library of Congress can I find the full version? :poke:
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It didn't fit. We had to store it elsewhere.

Every Known Item In Raiders Of The Lost Ark's Warehouse
 
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cpachris said:
Only 3 weeks after the initial fill-up, but I can already tell that I will want to tackle some type of automation for pH control. Tired of handling acid every other day already. Can't even imagine how I'll feel in a year. Anyway, what I'm looking for is:

- advice/comments from those that have tried it. what did you try and how did you like it?
- thoughts on CO2 vs Acid feed vs Other?
- links to any good threads discussing the above

Edit by Jim R.
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Geday Chris and welcome to the forums.

What pH are you targeting?

If you’re following the TFP recommended levels and your FC/CyA ratio is per the FC/CYA Levels your can happily run a pH of 7.8 which will reduce your acid use.

New plaster pools do consume more acid but after a while you can reach a happy balance where you’ll use very little acid and all that fancy equipment and the problems that can come with it will be almost redundant.
 
@Dirk
I vaguely remember that you and I (and many others) had weighed in heavily on this topic a while back. Actually back in Dec 2020. :p
After attempting to engage my own memory banks and doing some searching here, I finally found the thread where @JoyfulNoise had made the most compelling case for not dosing acid while the SWCG is producing chlorine.

Here is that link for anyone that wants to read pages and pages of back and forth theories on the topic. https://www.troublefreepool.com/threads/ic60-measuring-salt-level-often.218865/post-1948006.
However, I'll quote the most important part below if you want to get right to the heart of the matter.
tloomos said:
Can you explain this one? Why can't acid be added while the SWG is generating chlorine?
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@tloomos
Here is your answer per @JoyfulNoise...

"So why should an SWG turn off when acid is being injected? Well, again it's a little complicated but there are two very good reasons to do so. The first is based on the chemistry above. You really don't want to run a chlorine generator in a low pH environment or else all you will do is create a lot of undissolved chlorine gas that will bubble out of your returns. Chlorine gas leaving the water will cause the pH to skyrocket and this is what is termed as the "short pipe effect". The other MORE IMPORTANT reason to not inject a strong mineral acid while generating is that you will strip off the transition metal catalyst from the plates by doing so. The TM catalyst normally forms a conductive oxide layer on it's surface that allows it to aid in the formation of chlorine gas. Acids will strip away that oxide which is why I always suggest to NOT use strong acids to clean the cell. However, when the cell is running, the anode will continuously regenerate that TM oxide layer from the freshly exposed TM so, in effect, a constant stream of highly acidic water will continuously strip away the catalyst layer when the cell is electro-chemically generating chlorine. Normal pool water at a pH in the 7's does not do this or does so at such a low rate that you would have a hard time measuring it. Drop the pH while the cell is running and you will increase that dissolution rate rapidly and completely hose your SWG plates.
 
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MyAZPool said:
@Dirk
I vaguely remember that you and I (and many others) had weighed in heavily on this topic a while back. Actually back in Dec 2020. :p
After attempting to engage my own memory banks and doing some searching here, I finally found the thread where @JoyfulNoise had made the most compelling case for not dosing acid while the SWCG is producing chlorine.

Here is that link for anyone that wants to read pages and pages of back and forth theories on the topic. https://www.troublefreepool.com/threads/ic60-measuring-salt-level-often.218865/post-1948006.
However, I'll quote the most important part below if you want to get right to the heart of the matter.

@tloomos
Here is your answer per @JoyfulNoise...

"So why should an SWG turn off when acid is being injected? Well, again it's a little complicated but there are two very good reasons to do so. The first is based on the chemistry above. You really don't want to run a chlorine generator in a low pH environment or else all you will do is create a lot of undissolved chlorine gas that will bubble out of your returns. Chlorine gas leaving the water will cause the pH to skyrocket and this is what is termed as the "short pipe effect". The other MORE IMPORTANT reason to not inject a strong mineral acid while generating is that you will strip off the transition metal catalyst from the plates by doing so. The TM catalyst normally forms a conductive oxide layer on it's surface that allows it to aid in the formation of chlorine gas. Acids will strip away that oxide which is why I always suggest to NOT use strong acids to clean the cell. However, when the cell is running, the anode will continuously regenerate that TM oxide layer from the freshly exposed TM so, in effect, a constant stream of highly acidic water will continuously strip away the catalyst layer when the cell is electro-chemically generating chlorine. Normal pool water at a pH in the 7's does not do this or does so at such a low rate that you would have a hard time measuring it. Drop the pH while the cell is running and you will increase that dissolution rate rapidly and completely hose your SWG plates.
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Thanks for finding that. Good refresher. "...hose your SWG plates." is what stuck with me all those years...
 
I would suggest that if you want to dose acid independently of the SWG and not care when one or the other is running, then simply move the injection point past the SWG. It also better protects the SWG from constant low pH during dosing. Just make sure the injector has a good check valve on it.
 
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JoyfulNoise said:
I would suggest that if you want to dose acid independently of the SWG and not care when one or the other is running, then simply move the injection point past the SWG. It also better protects the SWG from constant low pH during dosing. Just make sure the injector has a good check valve on it.
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In my setup, the acid Dosing pump injects after the SWG. But from the other posts it sounds like that's still a problem because it's mixing the acid with the freshly generated chlorine? I can easily set the automation so the acid pump runs when the SWG is not running if that's better/safer.
 
tloomos said:
I can easily set the automation so the acid pump runs when the SWG is not running if that's better/safer.
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It would be.

Pentair recommends their IntellipH acid injector come before their IntellliChlor SWG. Though I have no idea why. They can spec that because they have this problem solved for their brand of stuff. What else do they know that we don't? ;)
 
I think it’s primarily a safety and ease of installation choice. Return plumbing can get complicated with pool/spa combos, waterfalls, deck jets, etc. and you want to ensure that the acid injector will always have water flowing past it no matter what particular feature is running. You don’t want a “dead pipe” with acid being injected into it accidentally. As a manufacturer, Pentair has to “design for stupid” because you can never know just how dumb people are …
 
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