The sump has a pinhole leak, running from 1 compartment to another, I give up trying to bung it, will probably fill with crap when its in operation anyway.
Tomorrow ill get the electronic switching gear.
I found a problem, the little pumps I bought to do the job, they are not powerful enough to return water 5 feet into the air and back into the tank.
Is there a formula for working out how much lph you lose with height?