black tank roof

It is not a closed system it has a vent. If your toilet seal is good, the system vents out when the pressure in the tank goes up due to heat, chemical reaction, or increase in volume and sucks air in when the drain valve is pulled. I do not have a cyclone vent cap but my opinion is they are an unnecessary expense. A piece of wire mesh to stop birds and critters from clogging the vent is all that is needed.

Bobbo wrote:
I have had these since I bought the RV and never had a problem.

Same here. Those Cyclone vent caps are supposed to draw the fumes from the tank but it is impossible. The waste tank is a closed system, for fumes to be drawn from the tank it would create a vacuum and that isn't going to happen. The Cyclone is a tax on gullibility.

Mine came with the OEM caps and have served me well for the past 10 years. They are similar to the ones Bobbo showed.

I have had these since I bought the RV and never had a problem.

My bad it was not a tornado it was a cyclone

Sorry

x2 on the 360

I've found the 360 Siphon Vent to be very effective. No moving parts to fail...

The Tornado is not a roof vent, it is a tank cleaner that sprays water into the tank, hopefully cleaning it out. I have used one for several years. The first died in about a year when a plastic part broke. The replacement had a metal part that replaced the old plastic part. This Tornado has lasted several years.

My RV came with roof vents for both the black and grey tanks.