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Is it possible to use a pair of Tuya water leak detectors & two irrigation timers (TM1 - out & TM2- in) to create a setup to auto-cycle aquarium water?

My idea is to have the two leak sensors located near the top (T1) and near the bottom of the tank (B1).

  1. T1 & B1 are typically submerged in water and always armed.

  2. On a weekly cycle, TM1 starts pumping water out till the water level goes below B1. B1 is disarmed at this point. T1 is also disarmed.

  3. Disarming of B1 triggers TM2, to start pumping water back into the aquarium.

  4. The water level continues to rise till it reaches T1. T1 get armed at this point and stops the inflow of water through TM2.

Onto weekly repeat now. Does this sound like a feasible idea? Has anyone designed something similar?

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    sounds like it should work ... please ask a focused question ... this site does not allow opinion based questions, such as yours
    – jsotola
    Jan 14 at 18:09
  • You might want to try using an ultrasonic sensor connected to an nodemcu running tasmota. This setup could output the actual distances from the sensor. Jan 24 at 17:44

3 Answers 3

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It should work depending on how fast the leak detectors respond. They are not designed for this purpose and may well be too slow to respond.

Do some tests and measure the response time. You may have to adjust the height of the sensors to cope with the lag.

A couple of float switches would be more low-tech and responsive. Thats the way I would do it. You can get miniature ones on Ebay etc. I got some recently to auto-fill my tiny pond as the water evaporates, this were a miniature version of whats in the toilet. In your case, you would want the ones with a clean contact so that you can connect them to your automation system.

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I wouldn't trust it. A typical electronic water sensor detects conductivity between two probes. The bottom sensor could stay wet even after the water level goes below its probe tips, perhaps due to algae, slime, or a bit of debris like a leaf stuck across the contacts. If that happens the sensor wouldn't shut off, and you could pump the tank empty before the sensor is dry.

You could mitigate the risk of sensor failure by locating the pump inlet only as low as the minimum water level you're willing to let it get to. But the pump will run dry while the sensor continues to signal its contacts are wet, and most pumps aren't designed to run dry.

As Rohit suggested, there are other, more proven technologies for detecting water to pump.

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    This is probably the big issue. Even without algae/slime/whatever on the pins, they'll likely stay wet for a while due to water tension. Also, leak detectors are designed to notify when wet, not when dry, so they're not really tuned/designed to dry quickly.
    – FreeMan
    Jan 16 at 19:01
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This is highly dependent on your specific model of leak detector as they all seem to have different implementations as to how they respond after the initial 'leak detected' alert is sent.

I have one LoRaWAN leak detector that polls every hour when there is no leak but once a leak is detected it switches to 1 minute updates until the leak is no longer detected. That kind of behavior would quickly drain the batteries on any leak detector you intended to leave submerged most of the time. This behavior was not described in the documentation so I had to actually purchase the leak detector and test to find out.

You should be able to use the leak detector for the upper limit but your best bet is to use a float switch for the lower limit as @Rojit recommended and ensure you put a realistic time boundary on how long the pump-out and pump-in processes can run in order to avoid disaster.

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