The most common cause of failure of submersible pumps is water leaking into the motor along the shaft seal. Magnetic-drive pumps avoid shaft seal problems and do not burn out when claw parts or seaweed pieces jam the impeller blade, as can happen with conventional drive pumps. Gas Disease Gas disease in lobsters results when water in the tank becomes supersaturated with air. It occurs when there is an air leak in the water pump intake. High pressure head contributes to the problem.
Mortality occurs in hours or days depending on the severity.
A percolation filter can help de-gas.