Another method is to attach a float valve to a second drum. This allows one drum to be used just for dry waste and the second drum just for wet waste.  The Drum Vac when configured for wet and using the dual float valve system will shut-off the air when the drum is 97% full as the floats rise.

The single float device in the second drum prevents fluid from travelling across to the dry drum. Useful in gutter vac situations.

The float valve system does not affect the reverse air blast filter cleaning so the unit can have the best of all worlds. Wet and dry and reverse filter cleaning. No other drum vacuum system in the market can do this.

Once the second lid with the float valve is in place, the unit is ready for all wet and dry waste.