Ideally, tank should be within...
6' of the toilet (that's 6' feet of hose, not just 6' "as the crow flies"). Absolute maximum is 10'...and that's a stretch that requires extra flushing to clear waste out of the head discharge line. The macerator should be as close to the tank as possible to minimize the time it takes to prime. The longer it takes, the more dry friction heat wear on the impeller. However, it should not be connected directly to the tank. Install a y-valve in the pumpout line between the tank and the macerator. The closer it is to the tank, the less hose there is for waste to sit in. It should always be aimed toward the deck pumpout fitting, and the overboard discharge thru-hull should always be kept closed except when actually dumping the tank. If any part of the tank is below the waterline, there should also be a vented loop in the overboard discharge line between the macerator and the thru-hull that's at least 8-12" above the waterline at any angle of heel.
