Most cleaners operate quite hot and evaporation is a big factor. Put a barrel in the tank, and manually get the level where you want it. Then pull the barrel out, and set the probe so it will add water when the solution drops below this level. Thanks for your reply, Ted. My cleaners are controlled by conductivity probes, and it is the level of the solution that needs to be controlled.
Evaporation draws the solution level down so far that the probes are exposed.
I have extended the probes in one installation, but the platers just let the level fall below the middle of the barrels. The information I need is for some kind of valve or something I can install and depend on to keep the level up. One of the most efficient setups for automatic barrel plating is a cleaner tank with an overflow weir about 4-6 inches wide on one end. A recirculation pump can be fed from the bottom of the weir to the top of the cleaner solution on the other end of the tank. Clayton Valve Company, based in Canada, manufactures an excellent float type automatic water valve utilizing a pressure diaphragm cut off valve.