I run 1.2 to 1.3 in my tubs and have 3/6 level racks in my garage. I clean once every seven to ten days and have no trouble at all with the odor. I keep my adults on a mixed bed of kiln-dried pine pellets and aspen bedding and the nursing moms/babies on straight aspen to keep from clogging the babies noses. I've tried the vanilla in the water and didn't notice a difference at all doing that. The rats have an odor; mostly warm animal but it can get a little rank with their amonia (especially the adult bucks!) but it's manageable if you keep the bedding/tubs clean. They aren't overpowering as far as smell and if it gets to the point where it is, you've let the tubs go too long without cleaning. I feed mine the Native Earth 4018 and straight well water and they do great on that as far as litter size and smell, within the constraints I mentioned above. I also keep a fan on mine circulating the air constantly to keep them cool and it aids in the odor once they're getting close to cleaning day. I dunno...that's what works for me; give it a shot and see. If it doesn't work out, feed or sell them off and then you'll know, lol!