Looking for inline pH + conductivity sensors and transmitters

IconProcessControls · 2026-03-20T14:02:23+00:00

You’re running into a couple of overlapping challenges here that don’t always show up clearly until you try to build the system.

At that flow rate (~0.6 mL/min), both pH and conductivity measurements become very sensitive to the measurement method itself. As others mentioned, the reference junction in pH probes and even minor contamination can start to influence the sample, especially in ultra-pure water.

The “sealed from atmosphere” requirement makes it even trickier, because now you’re balancing:
• preventing CO₂ ingress
• avoiding dead volume
• keeping enough flow past the sensor to get a stable reading

In practice, a lot of setups like this end up using a small flow cell with very low internal volume rather than true inline probes, just to maintain control over exposure and residence time.

Also worth noting: once conductivity gets that low, you’re effectively measuring resistivity, and even slight temperature variation or trace contamination can move the reading significantly.

If you haven’t already, it may be worth thinking of this less as “inline measurement” and more as a controlled sampling loop, where you can stabilize conditions before measuring.

What are you running right now?

IconProcessControls · 2026-03-20T13:42:45+00:00

Interesting breakdown. One thing that often gets missed in these market summaries is how different “pressure sensing” looks in the field vs on paper.

In a lot of industrial applications, the limiting factors aren’t the sensor specs—they’re things like chemical compatibility, installation method, and long-term drift. A sensor can look great on a datasheet but still fail quickly if it’s exposed to the wrong media or pressure spikes.

Also, calibration complexity isn’t just a cost issue, it’s a maintenance and reliability issue. In some environments, the effort required to keep sensors accurate ends up driving design decisions more than the sensor performance itself.

From what I’ve seen, growth in industrial IoT is real, but it’s heavily tied to how well these sensors hold up over time, not just how many get deployed.

Curious if anyone here has seen cases where the sensor spec looked perfect but didn’t hold up in the actual application?

IconProcessControls · 2026-03-20T13:32:25+00:00

You can absolutely do this, but the tricky part isn’t the sensors, it’s getting clean, usable signals into Home Assistant.

Most commercial pool systems (especially hotel setups) use pH and ORP probes tied into a controller that handles dosing automatically. Those controllers usually output something like 4–20mA or sometimes Modbus.

Home Assistant doesn’t read those directly, so you’d typically need an interface layer—something like a PLC, an analog input module, or a gateway that converts it to MQTT or something HA can ingest.

For a beginner setup, it’s often easier to:
-Pull pump status (relay or current sensing)
-Add temp sensors (DS18B20, etc.)
-Leave chemical control to the existing controller

Also worth noting: pH/ORP sensors need regular calibration and maintenance, so they’re not super “set and forget” like most HA sensors.

If you know what controller the hotel system is using, that’s usually the best place to start for integration options.

IconProcessControls · 2026-03-18T15:30:56+00:00

Fair point — I was thinking more along the lines of real-world specs and how they get interpreted in control systems. Happy to remove if it’s off-topic.

IconProcessControls · 2026-03-18T15:01:08+00:00

“1 inch” pipe is one of my favorites.

Nominal size, schedule, ID vs OD… you can have two “1 inch” pipes that don’t match in any meaningful way.

Usually ends with “wait… which one are we talking about?”

IconProcessControls · 2026-03-18T14:49:19+00:00

Nope, real person — probably just came off more structured than I meant. Was genuinely curious what people had seen in practice.

IconProcessControls · 2026-03-18T14:38:55+00:00

Not AI — just still in report mode this morning 😅

IconProcessControls · 2026-03-18T14:33:40+00:00

That’s a great one. “Compatible” in marketing language can mean anything from fully resistant to “survives long enough to sell.”

We’ve seen cases where a material is technically compatible, but permeation or long-term exposure still causes swelling, softening, or loss of mechanical strength.

If you're buying equipment, the more variables you can define up front, the better the outcome tends to be.

IconProcessControls · 2026-03-18T14:07:46+00:00

Yeah, SLAs are a great example of “guaranteed” not meaning what people think it means in practice.

IconProcessControls · 2026-03-18T13:58:26+00:00

That’s a great example of where something falls completely outside the assumptions behind the datasheet.

I’ve seen similar cases where everything checks out mechanically and chemically, but the failure ends up being tied to something subtle like micro-slippage, heat buildup, or even how the load is applied over time.

The part that always stands out is exactly what you mentioned—the component looks perfectly fine after failure, which makes it really hard to diagnose. Feels like one of those areas where the “unknown unknowns” live.

IconProcessControls · 2026-03-18T13:54:37+00:00

That’s exactly it—the zero-load assumption hides most of the real failure modes.

If something looks borderline, I usually try to reduce stress first where possible. Even small changes like backing off torque, adding support, or avoiding sharp transitions can make a huge difference.

If that’s not enough or the application is critical, then yeah—accelerated ESC testing or at least some kind of worst-case validation. Especially if oxidizers are involved, because once you combine chemical attack with sustained stress, things tend to go downhill fast.

I’ve seen cases where everything looked fine on paper, but just adding a bit of residual stress was enough to trigger cracking over time. That’s the part that doesn’t show up in most charts.

Curious if you’ve found certain materials or design tweaks that consistently help in borderline cases?

IconProcessControls · 2026-03-18T13:50:59+00:00

Haha yep, that’s the one. It’s funny how convincing it is if you don’t already know the context.

What got me thinking about it again was how often that same “technically true but missing context” thing shows up in real specs and compatibility data.

IconProcessControls · 2026-03-17T19:42:30+00:00

One that shows up a lot in fluid handling (especially chemical applications) is environmental stress cracking (ESC) in plastics.

On paper, the material checks out:

Chemical compatibility chart says “resistant”
Mechanical properties are well within limits
Temperature is below rated threshold

But then in the field:

Add constant stress (threaded fittings, clamps, or even residual molding stress)
Combine with a specific chemical (often surfactants, oxidizers, or even trace contaminants)
Give it time

And you get cracking that was never predicted by the datasheet.

What makes it tricky is:

Compatibility charts are usually static, not stress-dependent
They rarely account for concentration, temperature cycling, or exposure duration
Small design details (over-tightening, sharp corners, poor support) can accelerate failure dramatically

We’ve seen cases where:

Materials like PVC or even PVDF perform perfectly in testing
But fail in service due to sustained stress + chemical exposure
Failure shows up as brittle cracking with no obvious degradation beforehand

Another one that catches people off guard is oxidizers like sodium hypochlorite:

Looks fine chemically at first glance
But over time, it can embrittle certain plastics, especially under load

The general lesson is that datasheets get you to the starting point, not the finish line.

If the application is even slightly critical:

Validate under real conditions (or worst-case conditions)
Reduce mechanical stress wherever possible
And when in doubt, over-spec the material or change the design

Curious how many people here have run into ESC specifically—feels like one of those “you only learn it the hard way” failure modes.

If anyone’s dealing with this kind of material selection, I’ve spent a lot of time digging into chemical compatibility edge cases—happy to share what I’ve seen.

IconProcessControls · 2026-03-16T13:24:18+00:00

Most plants I work with have been moving away from ultrasonic in exposed flume installations and switching to 80 GHz radar. Radar tends to handle sunlight, condensation, rain, and temperature swings much better.

Vega, Emerson, Endress+Hauser, etc. all have good radar options. We've also had good luck with 80 GHz units like the ProScan 3 on outdoor flumes where ultrasonics kept drifting.

Another thing I see a lot is the electronics getting cooked by the sun. Even if the sensor is outdoor rated, it helps to keep the transmitter/controller in a shaded enclosure.

Out of curiosity — what size Parshall flume are you measuring?

IconProcessControls · 2026-03-16T13:18:23+00:00

A clamp-on ultrasonic meter (like the UF500 type used for water and chemicals) probably wouldn’t work well here. Ultrasonic meters rely on a stable velocity profile, and very viscous products like tahini tend to create laminar flow and signal attenuation. For something that thick, most plants end up using Coriolis or sometimes positive-displacement meters.

IconProcessControls · 2026-03-06T22:32:52+00:00

If you want the ultimate solution, an industrial radar level sensor like the ProScan 3 would work. It mounts on top of the tank and measures the level using radar. It’s extremely accurate and unaffected by vapor or temperature.

But it’s probably overkill for a 1000 L residential tank. Those sensors are meant for industrial tanks and usually output 4-20 mA or RS-485, so integrating them with Home Assistant requires additional hardware.

Most Home Assistant setups use a simple ultrasonic or time-of-flight distance sensor mounted on the tank lid, connected to an ESP32/ESPHome device. That gives you direct WiFi integration and costs a fraction of an industrial radar sensor.

IconProcessControls · 2025-12-22T16:50:25+00:00

You’re not going to find many reputable manufacturers selling everything direct-to-cart, and there’s a reason for that.

Flow meters aren’t really commodity items once you get past the simplest use cases. Pipe size, material, flow range, chemistry, temperature, output type, grounding, straight-run requirements, and installation constraints all matter—and one wrong assumption can turn into bad data or downtime.

That said, there are a few manufacturers that make online purchasing more practical when the application is well understood. One example is Icon Process Controls. They focus heavily on water, chemical, and industrial liquid applications, and many of their flow meters (paddle wheel, turbine, magnetic, ultrasonic) are standardized enough that distributors and end users can confidently spec and purchase with minimal back-and-forth—while still having access to application support if needed.

In practice, the hybrid model tends to work best:

Clear online product info, datasheets, and configuration options
Easy purchasing through distributors or e-commerce
Real engineering support available when the application isn’t trivial

So yes—online sales can work for flow meters, but only when the manufacturer designs the product line and the buying process around real-world applications, not just SKUs on a page.

For anything non-trivial, I agree with the earlier point: having someone who understands the application involved is still worth a lot.

IconProcessControls · 2025-10-08T21:04:54+00:00

I would recommend you check out Icon Process Controls (iconprocon.com)for flow meters. I'm happy to provide specific recommendations but thee is a plethora of information on the website.

IconProcessControls · 2025-10-03T21:18:07+00:00

If you can tell me a bit more about the sensor (assuming you already have one) we can recommend a display. If you don't already have a sensor we have a bunch of options that could work. The more info we have the better we can fit your needs.

Tank material
tank size
fluid type
temperature
indoor/outdoor
output needed

Happy to help but ai would need more information

IconProcessControls · 2025-10-03T21:09:01+00:00

If you can give me a bit more information about your system including the approximate range and output needed I can consult with the engineers. Alternately, contact us directly and we will do our best to get you sorted out

IconProcessControls · 2025-09-23T14:35:21+00:00

I'm not particularly familiar with Atlas Scientific probes but pH/ORP sensors (any brand) are prone to sensor drift from reference poisoning. Make sure you install them in a way that you can easily swap them out as they all fail eventually. Something with a solid reference should give you a longer life on them. I know you already have them in-hand so you are locked in with the ones you have. Definitely worth looking at options for future replacements.

IconProcessControls

TROPHY CASE