Hi Dale
We had a 360 sanitation vent on previous RV = It worked great!
So we purchased another sanitation vent for our new Alpine - But never installed it.
We found the following product (unlike any other product) and never needed the vent. = NO ODORS - USE in GRAY TANK.
http://www.vehiclespecialty.com/price_order.html
Check on RV.NET for other Happy Campers.
Sorry if this looks like an advertisement - It's just nothing out there matches it - they even use it in boat bilges, if you know how they smell!!
Rick