draining black / grey tank with sewer hose

[seaswirl]

this weekend I camped at cherrystone cg in VA, this morning I was emptying my tanks and when I was opened the valves, the hose was just filling up, it wasn't going down the sewer line, it seemed like it wasn't venting correctly, I had to actually close the valves, and lift the hose and shake to get it to go down the drain. what would cause this, could the sewer gases cause this, do I need to open the drains in the camper to vent? it finally emptied, but after I had to do it a few times, I had the support, and it was elevated enough to empty. anyone know what could cause this

[troutslayer]

I'm gonna take a guess and say that all of the solids were the first to come out of the tank. You may want to use a little more water when flushing. These toilets don't put as much water per flush as you might think. I know we can go 7 days, easily before dumping on a 38 gallon tank and it's still not full. Just before I dump the black tank I put one gallon of water in the bowl then do a power flush in order to stir things up a bit. I do this twice and then dump. I also use a product called The Sewer Solution which is a water macerator, of sorts and helps by putting more water down the pipe while empting the tank. Good luck!

[RedHorse1]

Like Trout I also have a Sewer Solution. It sounds like you are using a traditional "slinky". Drain the tanks one at a time starting with the black tank. Use plenty of water when flushing the John otherwise the "solids" may clump up and you'll have a "poop pyramid". It's possible your roof top vent is blocked but since it's a '14 seems unlikely. I can't say what drop is needed to keep things moving down the slinky but like a house sewer, too much and the liquids drain off too fast to carry the solids and too little and there's not enough movement to move the solids. I understand it's pretty common to have to "walk the slinky" to move the stuff downstream. After dumping the black dump the grays. Their water help to rinse the slinky.