Sensing water temperature

Hi, I have just purchased a 60w Chinese machine, now looking to set it up.
Appologies if this is a stupid question, but should the temperature sensor be connected to the flow or return tube? Does it make a difference?
Hope someone can advise.

Both are OK and will not cause any problems, but in my opinion it is better to have 2 sensors, one in the inlet and one in the drain, so you can see exactly how many degrees the water in the tube is warmer, that should be a maximum of 3 ° Celsius otherwise the water flow must be increased.

Thanks, now back to the shops…

If you only have one, I’d put it in the return line. It will give you a better view into the tube temperature than the supply line.

Thanks Rick, that’s saved me rushing out. I’ll start with the return line.

I picked up a dual digital aquarium gauge from Amazon for $12 USD, and put in line sensors in poly fittings. Having the delta across the tube gives me not only the output heat, but a good idea of how much heat I’m putting into my cooling system. I did the DIY mini fridge, and knowing the delta tells me how long I can cut before I hit my upper limit. ( Wrong size bucket has limited my thermal mass until I get a custom tank built. )

I did actual in line probe fittings with mated poly fittings at first, and when I moved / remade my bulkhead fittings I incorporated them into those fittings.