[folivier]

Clarke's classic I think has separate grey and black tanks.
Your '98 should have 1 large combined tank where all effluent goes into. It is usually sized a few gallons larger than your potable water tank.
You should also have a sight glass (probably just plastic tubing) on the curbside in the Aquahot bay. This gets dirty and needs to be changed out once a year or so. Easy to do, just dump, tilt the coach so passenger side is higher and change it out.