Custom Level Controllers are not needed for the operating logic, but which works perfectly well, but physical characteristics like the mounting on tanks, the enclosure, and connections can all be changed.
ZERO DEPTH CUSTOM LEVEL CONTROLLER
Custom mounting plate elevates the pipe mounting point which allows adjustment of the float switches to achieve a depth of zero. (so the liquid level can be right at the tank rim)
The working depths range from 5 to 7 inches. The intended range that the level is to be controlled is within 1/2 inch.