We have a 2003 Sea Breeze 32 foot and we bought it used. We have had it three years and it has been a great RV. It was our first but we made a good choice when we bought this coach. We have a banks system added to the triton V10. We are now in the Yukon heading for Alaska. We are having some problems with the sense indicators showing our holding tanks not being empty. I have read some of the discussions and we flushed the tank with a hose and the flush tank attachment and when we leave tomorrow we will try the bag of ice but here is my question. We notice a valve to the top left of the sewer connect and it reads tank flush. What is that and how do you use it?
I am sorry National went under they designed a nice rv. When we bought this Rv we had never done this before but my husband wanted to so we bought it. I gave him one year to see if we would like it. That was three years ago and I love it. You meet the nicest people.
Thanks for National forum.

Tank flush provides spray of water into the black tank while you are emptying. Hook up drain to sewer and open to empty black tank. Hook up a hose to the tank flush connector and turn on the water. It will flush the tank. Shut off the water, disconnect the hose then close the black tank valve. Not sure if it will clean the sensors (they work poorly most of the time) but should clean the tank.

Welcome to the forum, glad you found us. There is much info available here, jump right in with questions or comments. Accuracy of the tank monitors is an ongoing problem for National owners. I refer to the Grey tank monitor to determine when to dump, this tank is usually fuller than Black. After trying to retrofit an aftermarket sensor system with no success, I learned to live with the problem.
Looking forward to hearing of your trip to Alaska, please keep us posted.

I would have to agree about the sensors. They're useless most of the time. I just drain my black water every four days when staying any length of time and dump the grey water once a day. When on the road for several days, I empty both tanks every morning before I start my drive. I still have the directions on my tank flush fitting. It says to leave the water hose turned on for two minutes after draining the black tank while the sewer valve is open. However, I often close my sewer valve with the flush out water running for two minutes and then open the valve again. That really flushes things out.

In my '99 Tropi-Cal 6371, I found that the tank flush has a back-flow preventer between the hose hook-up and the tank. That back-flow preventer was installed backward, so it just pressurized the hose, with no water getting to the tank. The valve is located behind a panel, behind the toilet. Once I turned it around it works great. It cleasn my sensors so well, I wish I had one in the gray water tank too!

Fred, Thanks for the tip on leaving the tank valve closed. I have been reluctant to try that since the directions say to leave it open, but I think it would help move any remaining "sludge" buildup out of the tank. It seems that it would also work well for adding a few gallons of water before putting the chemicals in...

Added shortcut to RV Systems and Appliances for better coverage.

TropiCal-Tex - I think they don't want you to close the valve with water running into the flushing system because it could cause water to back up into the toilet if left on to long. When I want a really good flush out, I have left the valve closed until the black water tank is almost full and then opened the valve. I want to add a note of caution. You have to closely monitor what's going on so you don't overfill the black water tank. It seems to sometimes help clean the sensors.

I think we all have this "tank flush" thing...and after gong thru the rigarmarlole of turning off the hose, unconeecting it and reconnecting it, flushing the tank and again turning off the house and reconnecting it to the water in (whew)...I found an old garden hose. cut it to approximate size, and bought some plastic hose ends (repair) and a brass "Y". Made a manifold of sorts, tie-wrapped the brass "Y" to the piping and now, after dumping the tank, I just turn a lever on the "Y" and do what I have to do.

Wish I could send a photo....but with dialup....

I did the same thing. I just make sure I have water flowing to the black tank before I turn off the water that feeds the coach so there is no chance of contamination. In turn, I turn off the water going to the black tank before I turn the water back on feeding the coach.

I have a quick disconnect connected to an in-line shut off valve which I leave hooked up to the tank flush fitting. Some RV parks have two water spigots and the ones that don't I use the Y adapter at the spigot for a second hose. When done flushing the tank, I close the valve at the Y adapter and then close the valve at the tank flush fitting before disconnecting the hose. I always use the same hose for this and never use it as a water supply to the motorhome.