Electronics - Water level alarm

Given how often I like to try to run my fish tank dry, I think it's time I started looking into a way to improve the situation.

I'm thinking either an alarm of some kind, or perhaps a way to turn off the pump if the water level gets too low.

My pump is mains voltage, so I don't really want to mess with that because I have no idea what I'm doing and quite like the whole living thing I'm currently doing., so I guess that's already limited my options to creating some kind of alarm. It wont solve the problem when I'm not home, but it might give me a fighting chance to catch leaks or some other problem before it harms the fish or my pump.

For anyone contemplating an aquaponics system that's feeling a little put off by everything that goes wrong in my system, please keep in mind that it's all about either doing things for 10 cents when I should have spent 15 cents, or because I keep trying different things. Just keep in mind the point of my doing this stuff is so that other people don't have to. If I kept to my original layout of a grow bed over a fish tank, a leak would mean water would run back into the fish tank, so all my problems are because of experimentation rather than any kind of inherent problem with aquaponics.

I still have to finalise the design, and build my swirl filter to return solids to the grow bed rather than having them sent to the NFT tubes, so there will no doubt be a stack of shiny new potential points of failure still to come, so stay tuned.

120 things in 20 years, Just idle thoughts about electronics, and water level alarms


  1. This is what I use:

    I have one in my fish tank sensing low water and one in my GB sensing high water.


  2. I like the price. Is there a magnet in the float to trigger a switch? Is it all sealed?

    - 120ThingsIn20Years on someone else's computer

  3. I think it must be a magnet, and it's sealed.
    I bought 15 of them from China for about $20. No HSM's so far! The set up is a small aquarium pumping to a glass bowl with a peace lilly, then a water bridge returning to the tank. One float in each. If the bowl is too high the PLC shuts down the 240v to the pump for 20 minutes, then reassess the data. If the tank is too low it does the same...but I think I might put in a screachingly loud alarm as my air pump siphoned 20l out one afternoon.


  4. The problem with alarms is the going off when youre not home thing they tend to do.

    - 120thingsin20years still on somebody elses computer

  5. Thank you so much for writing a lot of this good information!
    Barra Lures


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