Gene,

We too, tried Thetford's Green, EnviroChem and several other more environmental friendly chemicals, but have resigned ourselves that until we hear differantly we are going to use the formaldehyde based Thetford Blue product. It's the only one that comes close to controling odor, especially as the heat of summer sets in. I'm not extremely fond of the purfume Thetford uses in the product, but it beats the alternative. Now that I have presented nothing new, I would suggest two things that I'm sure need not be said, but you never know.

We: 1) keep the toilet seat down- Thetford has made the seal somewhat tight on this recirculating unit probably for the very reason we are discussing, and 2) we always keep the exhaust fan running.

Also, it's my intention to fabricate a small ductwork using a piece of plastic square tubing to be secured to the base of the tub and a small flexible short hose (1&quot affixed to the rear portion of the toilet's lid. Of course, I'll have to cut or drill a hole in the lid. There will need to be some sort of fixture devised to act as a siphon type vent to be used in conjunction with the small 12 volt exhaust fan located in a convenient spot near the bottom of the tub. I think it just might help. I'll let you know if it does or doesnt work.

happy trails..............George