Float Switch needed - DIY ATO

[lngrhaul]

do you need a vertical or horizontal float switch to make it work?

[Snaz]

I used the vertical ones as pictured in the Ebay link. It sits in my back compartment and is working a treat. This last week my little 12 gallon tank is going through about 0.75 gallons a day of fresh water as I blow across the surface with fans to keep it cool.