I have one that works great then I bought two more and neither of them work consistently. I am going to have Able (skunkmere on here) make me new ones and throw the JBJs in the trash.
Anything with a float switch has a good chance of failing, custom made or not. It's the salt/mineral creep. I think it helps when you have your top off water output spraying water right on your float switches to keep it salt creep free (provided youre not toping off with kalk water).
I thought about getting one of these too... I have my top off gravity fed from a 5 gal jug connected to a float valve. Is there anything wrong with this set up? should I switch to the JBJ? It seems to be working fine and parameters are good. Jeppun let me know what you think of the jbj if you do get one.
Another alternative to ATO float switches is using a dosing pump. You just estimate or calculate the amount of water you lose in your sump/tank and set the dosing pump to pump water throughout the day to keep sump water level the same