When it come to odor out the tank vent...
VacuFlush is no different from any other toilet...'cuz the air in the tank is displaced out the vent by the incoming flush from all toilets. So the type of toilet has nothng to do with whether that air stinks. And if you vent the tank to keep it aerobic, you don't need a filter...which is actually a bad idea on a sailboat anyway, 'cuz filters are toast if they get wet, and heeling makes it hard to keep it dry, 'cus it sends waste into the vent line. If you're using it correctly, 3-4x more tank capacity is a wee bit optimistic.The two biggest mistakes most V/Flush owners make: 1) Just "popping" the pedal...letting go the second the bowl contents are gone. The pedal not only opens the dome the bottom of the bowl, it also is the flush water "faucet"...so it should be left down at least 3-4 seconds following urine only, and 7-10 seconds following solids and/or any TP....to completely rinse 'em out of the pump housing around the bellows and the duckbill valves. It's also important to add plenty of water to the bowl ahead of solids and/or TP...'cuz the suction splatters the bowl contents all over the inside of the system, and the flush water flow isn't is enough to completely fill up the hose. So you need at least a couple of quarts of water with the bowl contents.So while SeaLand claims it CAN use "as little as" one pint of flush water, in actual practice it actually needs considerably more than that if you want prevent problems.2. Easing the pedal back up. Just let it go. It's spring-loaded for a reason: to allow the dome to snap back into place with enough force to seat and seal the bowl. Easing it up can leave it incompletely seated, resulting in a air leak...over time the spring develops a "memory" that won't let the dome seat and seal.I don't have anything against a VacuFlush...we were dealers for nearly 10 years, and it was the toilet on my last two boats. However, there are now a number of other toilets that offer everything it does and MORE for a fraction of the price...and have all the "innards" in the bowl assembly, not scattered all over the bilge and/or taking up valuable storage space. IMO, the best high end electric toilet on the market right now is Tecma...an Italian toilet that has a "grinder" (they don't call it a macerator) that'll even chew up a tampon and a pump that'll move bowl contents up to 50 vertical feet and over 200 linear feet. And has a one piece china bowl and pedestal instead of only a china bowl on a plastic pedestal. Retail is about $800...or about 65% the price of V/Flush, even if you install it yourself. Check 'em out here: http://www.tecma.net/nautica/index.html