Some helpful tips for using the Sani-Con that I've learned from others, or learned from experience:

1.  Some obvious things first...  Don't run the Sani-Con pump when the system is dry or when the sewer valves are closed, or when the tanks are empty.  Don't run it for longer than 15 minutes without letting the motor cool for 15 minutes.  Do remember to remove the green cap from the end of the discharge outlet.  (You'll only make that mistake once.)

2.  When flushing always open the gray tank first.  In case something goes wrong, and you have to remove the hoses, you'll be glad you didn't start with the black tank.

3.  As soon as you confirm everything's working OK, open the black tank and close the gray.  Empty the black first.  That way you can back flush the black tank with water from the gray tank.  After back-flushing (with the Sani-Con off), then close off the gray tank and empty the black tank again.  Repeat this 2 or 3 times each time you flush the tanks.  The soap in the gray water will wash out the black tank and help to keep it clean.

4.  As you pump out the black tank, use the fresh-water flushing system.  That will help to move everything through and help to prevent build-up inside the tank.  After both tanks are empty, I like to continue to flush with fresh-water to clean out the Sani-Con hoses.

5.  The large black hose going from the sewer outlet to the Sani-Con pump is porous, and can absorb waste odor and start to smell after a while.  If this happens, try the following procedure to clean it:

a.  Completely flush the system.  Close the tank valves.

b.  Fill a sink with a mixture of chlorine bleach and water.

c.  Pump out the gray tank, leaving the hose full of the mixture.

d.  Let sit for a day, or at least overnight, to clean the hose.

6.  Sometimes the pump can jam up if something gets caught in it.  For that reason, it's good to flush the tanks thoroughly on a new motor home, using a conventional drain hose, before using the Sani-Con.  (Unfortunately, it's not uncommon for construction debris to end up in the black tank.)  If the pump does jam up, before you take it apart, see if you can reach the end of the pump shaft with a flat blade screw driver through the access hole on the side of the housing opposite the hoses.  Sometimes giving it a quarter turn or so, in a clockwise direction, will free the jam and get the pump rotating again.

Gray Water Bypass:  On most systems there is a small clear hose that goes from the large black hose, directly to the discharge hose and bypasses the pump.  (You can see it in this picture.)  The concept here is that, if parked for an extended period of time, this bypass hose will allow the gray tank to drain by gravity without running the pump. as long as the gray tank valve is left open.

There are a couple of problems that people have reported with this system.  Sometimes the inlet side of the bypass hose gets clogged or won't pick up the gray water.  Some people have resolved this problem by backing the nipple threads out one turn to make the bypass hose inlet flush with the interior wall of the fitting.  Also users have reported that the Sani-Con discharge hose has to have a fairly straight and level route to the campground drain for the bypass to work properly.  In addition, the bypass hose sometimes gets blocked, and the only solution is to remove and clean it out. 

While I'm a big fan of the Sani-Con system, I almost never use the gray water bypass for a couple of reasons.  First, with my water-guzzling macerating pump toilet, I don't really find it all that useful.  My black water tank fills about as fast (or faster) than my gray, so I have to flush the tanks anyway.  Also, as stated above, I like to use the gray water to back-flush the black tank.