i never heard that and i have spoken to many users of the system, they have float switches that activate the pumps, so if your floats get stuck then you have a problem, same goes for the multi flow, actually i havent seen a multiflow at any website for sale, only difference between the two systems is the pot size, MF uses 5 gallon buckets and EnG uses 2, this is key when buying and cleaning hydroton, aside from that you can grow same size trees, pot size will only matter in regular soil grows where the plants get root bound, i used to run aero, aero is king but i am an EnG guy now, trust me you wont be sorry