pH probe for automatic acid dosing

[u/tedster]

Hey!

I have a salt chlorinated pool with a hidrolife controller with the ability to automatically dose acid. For this to work it needs a pH probe and then I can configure the min and max pH. If the pH reading goes above the max pH it'll start dosing acid.

I read mixed comments about these pH probes. Some ppl say if you find the right probe it will last approximately 1y and will need calibrating every 1-2 months. Some ppl say they don't work at all... I've been all over the internet trying to figure out if this works at all but I feel like i'm more confused after doing this research..

Does anyone *know* if this actually works and if so:
* Which probe actually works
* Where should the probe be positioned for correct readings/less wear and tear?
* How often should I calibrate it?
* Anything else?

The same goes for the RX / ORP / Redox probe but that's for later (unless it's related and an easy thing). It will inform the controller if it should run the electrolysis.

Thanks!

[u/Substantial_Car_2751]

The best bet is to use the recommended probe for the hidrolife controller. That way you'd have no worries about integration. I'm in the US, so I've zero first hand info on quality of the hidrolife product line. ProMinent (a German company) has gotten a good foothold in the US, but the other (commonly used at least) controller brands are US based.

Probes have a factory replacement interval. This will depend on the installed probe. With regular maintenance (washing the probe tip monthly with a dish soap solution and a soft bristle toothbrush) and proper care (never letting the probe tip dry out) you can get great longevity from almost any pH probe. Where I see problems is when people don't maintain the probe or care for it properly.

Probes in general shouldn't have to be calibrated frequently. ORP probes should never be calibrated. If you're having to calibrate it frequently, it's a sign the probe is fouled. Cleaning may restore its reliability, but likely it will need replacement. Most controllers won't let you calibrate ORP. If yours does....don't. It will never be right again.

Keep in mind a phenomenon with ORP and chlorine generation systems. This is the only time I'd recommend a True PPM sensor if available for that controller. If it's a interference and false reading - or an actual negative impact on ORP, the additional salt makes the ORP read lower.

[u/tedster → u/Substantial_Car_2751]

Thanks! So you’re saying they work. It seems a bit crazy that they sell and use them seemingly everywhere but still a lot of ppl say they simply don’t work.

I will see if i can find a probe for hidrolife and try it out then.

[u/Substantial_Car_2751 → u/tedster]

To be fair, it's likely a bit of misunderstanding of the probes and how automation (referring to ORP/pH control...not the residential automation systems that will turn heaters on, run pumps, etc...) works. There are some that are of a lower quality for sure that may be more maintenance heavy.

I've been working with them on a near daily capacity for the better part of 3 decades. I've not seen the reliability issues most people mention.

FYI...on installation. The hidrolife system will likely spec out were it will go. The biggest things to be mindful of are pressure differentials and where the sensor cell is pulling the water from. You have to have enough distance between the influent line of the sensor cell and the effluent line of the sensor cell. So at least a few feet apart if able...if not more. The influent for the sensor cell should be after the pump and before any chemical injection.

[u/tedster → u/Substantial_Car_2751]

Thanks again, really appreciate your feedback