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By bilaldadar
Hi all,

Newbie here, please bear with me.

I have a 1000L water tank on the ground floor which pumps water to a 500L water tank on the third floor through a water pump attached to the source tank. The pump switch is in the house on the second floor. At the moment the setup is manual. A person checks the water level in the source tank and then flips the switch on the pump. When the upper tank overflows the pump is switched off.

I want to install a system that will monitor the water levels in both tanks and automatically pump up water based on boolean conditions as follows:
1. If water level in Tank A is above Upper Threshold
2. If water level in Tank B is below Lower Threshold
3. Switch Pump On
And then
4. If water level in Tank B reaches Upper Threshold
5. If water level in Tank A goes below Lower Threshold
6. Switch Pump Off

I am trying to go one step further than the traditional dumb float switch system by using electronics to display water volumes in each tank on a console inside the kitchen, preferably next to the pump switch.
If possible I would like to go another step forward and use the home wifi to post the display to a mobile app.

Any ideas?
By jremington
Liquid pressure sensors at the base of each tank can be used to accurately measure the height of the water in the tank. They don't suffer from corrosion, like DIY ultrasonic sensors.

Another option is a DIY or commercial capacitive level sensor. For DIY, see the attached article.
Columna 27 - Measuring Water level.pdf
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By hogwell
I had a similar situation.

In my case I needed to monitor a low output well, which dripped water into a storage tank in my basement from the pressure tank.
I wanted to measure the water level in the well, the pressure in the well pressure tank, as well as the water level in my storage tank.

After trying several ideas, I finally arrived at a solution that works, using two Arduinos linked wirelessly with two XBee Pro radios.

For the water tank level, I used a corrosion resistant version of the common HC-SR04 ultrasonic sensor mounted in the tank lid.
It is called the JSN-SR04T.
The echo timing used to measure the liquid level is pretty jittery, but I found that using an averaging algorithm in my Arduino sketch smoothes this out nicely.
I display the various measurements, including tank level, on a 16x2 LCD display on a Mega.

Measuring the well water level turned out to be trickier, since it was 200 to 300 feet down the well, much too far for the ultrasonic method and 100 feet away from the main Arduino.

I solved this with a second Uno that periodically turned on an air compressor to "pump-up" an open-ended 1/4" tube that stretched down to the pump.
An air pressure sensor (MPX4250DP) on this air line allowed me to measure the water pressure after "inflating" the air tube.

While there are many good relay shields and boards to start a motor (e.g. your pump or my air compressor), I found a neat power strip with an internal relay that's perfectly set up to use with a 5v Arduino. It is called the IoT Relay from DFI. (I got it on Amazon).

Now, I have real-time data about my multi-stage water system logged to an SD card and also displayed in Excel on my PC.

This is really overkill for what you want, I think, but maybe it will give you some ideas.