I just posted this elsewhere on the net because I am having this ame problem and am about fed up. To be sure to nip any black tank issues in the bud and avoid my dry caping phobia, I decided to "pre-charge" the black tank with ten gallons of water before we even left the house this weekend. I figured that at almost 1/3 full, we'd have a good amount of solution for the tank contents by the time we were ready to dump two days later. Upon leaving Sunday, I even topped the tank off with water from buckets until the black tank was completely full. Then to the dump station.
I made sure we drove around the campground a bit before dumping to help break things down. Then, I pulled the valve open and got a gush of a full hose for about five seconds - I could see through the clear connection I had installed. Then, a trickle... for ever. I added several buckets through the toilet and nothing but a 1/4 inch wide stream in the invert of the hose. With no hose connection for the tank flush, I was doomed. I added about 12 gallons of water through the toilet, but we never got much flow, and by the time we had to leave to avoid ticking off the guys behind us, the tank was close to 2/3 full. When I got home, it was constant flushing and bucketing to the septic, and close to two hours later, we were clean again.
I am wondering if we actually have an obstruction going on. I have heard of the "plug" drilled out by the fatory for the drain connection being left in the tank and causing problems. I just can't figure out how we have had this issue every time (twice) we have used this trailer. If we had another weekend left this season, I'd try the TP in the bag trick. We only use the RV toilet paper from Camping World, and although I do find a glob coming our now and then, it is not enough in my estimation to plug things up so bad that the water (liquid) almost completely stops.
I think that tonight I am going to fill the tank up 100% now that there is no waste in the tank and see how it drains with all water. Maybe I'll find it will slow up or stop, and that will support (or negate) my reasoning of an obstruction.
Is it possible the way it is plumbed is an issue? I can't see with the enclosed underbelly, but both the grey and black tanks come into a tee for the main drain, and the valves are on each opposing side of the tee. This is so frustrating, and now having to think about it all winter whithout resolution is going todrive me nuts. I wouldn't think it is the TP when it is RV approved, but why aren't any of you having issues? How can the TP break down on a two-day weekend?
Lastly, I see the venting issues some posted above. I noticed we has some heavy gurgling at the start of dumping, which makes me think this could be an issue, too. We didn't have the option to use the flush at this state park (no hoe connection available), but I don't see anywhere the performance or volume out of the factory flush when compared to the Tornado. We go in for a laundry list of warranty items nex weekend, and I hope they get it resolved, otherwise I'm done with dry camping.