Pool Water Temperature Monitoring

I was looking at finding a way to monitor my pool temperature using ST. I was thinking of mounting this: https://www.amazon.com/gp/product/B00P2QAR8C/ref=crt_ewc_title_gw_1?ie=UTF8&psc=1&smid=A33RI86K4PO1EO near the pool, likely in the skimmer and either using a dry box (anyone recommend one?) or that spray fill and then connecting it to https://www.amazon.com/gp/product/B008HODWBU/ref=crt_ewc_title_dp_2?ie=UTF8&psc=1&smid=A28PCZ3GGXGBES . I may have to add a small weight to keep that down?

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As far as the temp sensor, the industry standard for measuring water temp like in your application is to put the temp sensor in a thermowell to protect it against corrosion. The well is screwed into a female fitting typically welded at an elbow. But my guess is you won’t be able to do that with your piping if its pvc so instead a tee will be needed at an elbow or in a straight away with adapters to fit the well.

[quote=“Adam_Smith, post:1, topic:50080”] or that spray fill and then connecting it to

don’t know what you mean by this?

Why would it need to be enclosed, isnt the probe already corrosion proof? and the spray fill is plexifill? I used it to seal an ecolink sensor outdoors. Id likely go with an enclosure tho instead for this.

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Excellent point. yes your sensor is protected pretty well but the thermowell also gives you a clean installation and place to mount a junction (enclosure) box for installing the receiver and making the sensor terminations. It also allows for future replacement or service, etc. You are talking about weighting it down, etc. I was just letting you know the professional installation standards. My guess is the pool supplies place may have that well built in to a coupling?

Isn’t your skimmer out at the pool side?

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Swimming pool water is one of the most hostile environments there is. Much more so than the water that flows through the plumbing inside your home. The chlorine is one issue, but just as significant is the fact that pools generally have chemicals added all at once and then allow them to disperse through the pool through ordinary circulation. This creates pockets of really intense chemicals.

Add all of this together and you get something that you will probably hear me mention on every topic regarding electrical equipment near swimming pool: “galvanic corrosion.” It is not at all uncommon for homeowners to use regular plumbing meters near a pool and then for these devices to catch fire.

Consequently, in United States almost all jurisdictions have special safety codes regarding electrical equipment placed in the “splash zone” of a swimming pool.

It’s simply not enough for sensors, pumps, etc. to be waterproof in the ordinary sense. The safety standards have to be different to survive a swimming pool environment.

Add to that the fact that you should never put a battery operated device inside an airtight container unless both the battery and the device are specifically rated for that (batteries can and do outgas) and many DIY projects fail to meet code near swimming pool.

All of this put together is the reason why pool equipment seems to be so expensive. It’s expensive because it’s meeting a completely different engineering and safety standard.

So you’re better off purchasing equipment which is specifically rated for this environment.


I currently have a acu-rite floating pool thermometer that just is a simple wireless unit that floats in the pool. It uses AAA batteries and is sealed. Unfortunatly it seems to be losing its seal enough due to the direct sun exposure here in AZ. I thought if I mounted a waterproof box with the device inside, and had the sensor extending out through a waterproof seal it would work. I was planning on mounting the box inside the skimmer area, where it may get wet time to time, but is NOT submerged for any period of time. Technically my skimmer basket doesn’t do anything but is the connection for my pool shark. Anything floating or in direct sun is exposed to 115+ AZ days, and I have no intention of wiring this to anything other then a battery. I dont think you can galvanize a plastic enclosure.

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I temporarily have a cheap motion sensor with temperature sensor vacuume packed like freezer meat floating in the pool. its accurate at night when the sun isnt beating down on it and the waters top layer. It always moving around and detecting motion when the pump is running…and shows no motion a little while after the pump stops. its kind of nifty for a first attempt.


My Hayward Aqua control something or other simply has a temp probe hose clamped onto a hole in one of the tubes. Was way easy to install. I think that would solve the physical aspect. You can look those up online, I’ll try to find one now.

This guy http://www.acepools.com/products/hpx2169?utm_medium=cpc&utm_source=googlepla&variant=685040535&gclid=CjwKEAjw7e66BRDhnrizmcGc8VcSJABR6gaRfpvhMbT226-6lHgkR4dj5PR3TP-wO03s5jcQl2Q5_BoClGTw_wcB

What about this option? any reason why the fibaro solution won’t work?

anyone else try this?


i like the idea. i may take it on - install it in an unused chlorine float or something like that.

I’ve been using the Fibaro sensor with temp probe for several weeks now. I drilled a hole for the probe tip in one of these boxes and sealed up with some silicone gasket maker and dropped them inside the skimmer openings. With the exception of the enclosure screws rusting (probably will replace them with some stainless ones), everything has held up ok so far.




This looks really cool and would be great to know the pool temp. Is the unit submerged in water or do you just have the probe sitting in the water?

How do you keep the unit from moving, how is it mounted?

The box is air tight so it floats on the surface with the probe down in the water. I do not have it secured, the flapper door for the skimmer keeps it from leaving.

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I did almost the same thing ,except with the sonoff th16 ,i have plug the th16 on my pool pump and i just let the sensor in the water ,i ad to buy an extension for the sensor ,it cost me around 45 cnd.
sonoff th16 20$,sensor 5$ and metal water proof electrical box 20 $ to put the sonoff th inside.

I am using a sonoff Th16 to monitor my pool temperature after my fibaro door and window sensor quit working. I liked that the fibaro sensor when in my favorites on the smartthings app would show the temp right on the main page. The sonoff device handler shows the on/off option instead of the temp. Does anybody know how I would go into the code to change the postion of the temp show it would show first instead of the on/off option? I’m using the recommended device handler for the sonoff. Any help would be greatly appreciated.

You should be able to change the DH

Change these lines

details(["switch", "temperature", "humidity",
         "ip", "uptime"])


details(["temperature", "switch", "humidity",
         "ip", "uptime"])

i know this is an old thread but does anyone know where i can buy the fibaro door/window sensor that has the temp connection? their new model does not seem to have that anymore.

How is your temperature probe holding up? I’m thinking about doing the same thing but it looks like the Fibaro link is no longer valid… Do you have another sensor you recommend?

Unfortunately that version of the Fibaro door sensor is no longer available and the new one does not accept an external temperature probe. You should be able to find the old model on eBay though. That’s what I did for my Freezer monitor.