Abstract: Suspended solids are removed from a circulation line extending between an oil storage tank and a water reservoir. A filter is positioned between the storage tank and a circulation tank for collecting suspended solids carried by a circulated water stream from the storage tank. A pressure sensor and a transducer is mounted in a control unit positioned upstream from the pump and downstream of the filter to detect and out-of-range pressure condition and send a signal to the pump power supply for de-activating the pump. An alarm signal is generated alerting an operator of the low oil level in the storage tank or clogged filter.