Gray tank problems: mold and grease in the galley tank.
A sour gray tank will have a far worse odor than a black tank. It can be particularly bad in a motor home on the move. We cover why in another FAQ. Motor homes and small bumper pull trailers usually combine the shower and galley tank. 5th wheel and larger bumper pull trailers usually have a separate tank for the galley. Isolated shower tanks do not typically cause a problem. The easiest way to see if there is a separate galley tank is to look at the monitor panel. If there is a third tank it is the galley tank. Some units have a 4th monitor for a second bathroom black tank, but it is usually on a separate monitor. 5th wheels are notorious for placing the handle for the galley tank under the slide out between the two tires on the frame of the trailer. Seriously, that is where it is and that is probably the biggest reason that people leave that valve open in a park. The worst smelling tank we ever encountered was a galley tank. Lots of long-term resident or snowbirds in the parks like to leave the gray tanks open. If there is a washing machine in the unit, this may be mandatory depending on the plumbing. Leaving the galley tank open is ok with some precautions. The FOG, fat, oil and grease is going to stick to the walls of the tank and turn rancid eventually. When it gets hot it’s going to STINK. The solution is to shut the valve and treat it with TankTechsRx for a few days or weeks to clean it out. This should be a regular occurrence if you are in a permanent location. WE recommend whenever you are going to be away from the RV for a few days or weeks, treat the tank, let it fill naturally and leave it full the entire time you are gone. If you are a wanderer traveling from time to time, treat the tank long enough before you leave to get not more than a ¼ tank. An inch would be fine. The sloshing of the Probiotic laced water will clean really well while traveling. Treating this way will require a starter amount of 2 ounces every time. Only reduce to ½ ounce per treatment if you do not empty completely. You can safely leave the gray and or galley tanks open if you follow these simple precautions.