Tab 320 grey tank drain

immanence

Hi folks,

I love the separate black and grey water on the tab 320, but when I am at a site with water and sewer I figure I should just hook the grey water up to drain continuously. What is the best way to do this?

I have an aftermarket grey tank line cap that lets me hook up a hose, but would you just snake that into the drain? Seems a bit gross but maybe not and maybe I just need to devote a bag to the hose I use for this?

Denny16

Just use your sewer hose you normally use, open the grey valve and you are good to go.  That said, when it’s time to dump the black tank, you need to close the gray tank valve, and collect some grey water to flush out the sewer hose.  That said, I normally keep my valves closed, unless I am dumping the tank.  The only time I would consider leaving the gray tank valve open, would be during a long shower… 
 Cheers 

kottum

We have the later 320 with cassette for black water.  So I also have a garden hose adapter on the grey dump valve, and drain the grey tank with a garden hose (tossed the stinky slinky).  Normally, I leave the garden hose (a different color than fresh water hose!) hooked up to the valve, keep it closed, then drain the tank as needed.  Just stick the end in the dump drain enough to stay put, then rinse and wipe down that end when finished.

It's not normally allowed to leave the hose dangling in the open drain, unless you devised some sort of sealing fitting for the drain that would fit your garden hose.  I've owned such a device with a system called "Sewer Solution" that can drain both black and grey tanks through a small hose, works very well.  No large slinky needed. 

Doug

Bayliss

@immanence, my view is that the best approach is to keep your gray water tank closed as well, preferably until it is fairly full.  HOWEVER, there is nothing wrong with leaving it open all the time, either.  Your choice.

I let my gray water tank fill up (or close to it) so that I can use the gray water to flush out my sewer hose each time I drain the black tank.  When you need to drain the black tank, always do that first, followed by the gray water tank.  If you do not have hookups at a campground and need to dump your holding tanks at a dump station, it becomes even more helpful to have a fairly full gray water tank for the same reason - - - to have a good strong flow of gray water to flush out any black water tank residue that was left behind in your sewer hose after first draining the black water tank.

Even if you are not using the black water tank, it is still a good idea (in my view) to let the gray water tank fill up (or close to it) before dumping it as needed.  I say that, because if you just leave it open all the time, you are more likely to have residue from washing dishes, etc., ending up in your constantly nearly dry holding tank, not to mention in the sewer hose (because neither get a good flushing.)

Again, just my opinion, but based on many years of RVing.  Have fun!

P.S.  Can you post the year model of your trailer?  When you are camped at a private campground or other location that has sewer hookups at your site, you don't generally need a portable gray water tank (assuming that is what you referenced in the second part of your question.)  You just hook your sewer hose (e.g., a Rhino or Valterra sewer hose) directly between your trailer's sewer drain and the campsite sewer drain.  The portable gray water tank is generally for use when you do not have hookups (e.g., when boondocking or in a forest service campground), but occasionally need to drain your trailer gray water holding tank (or at least free up some holding capacity) and dump the portable tank at a nearby dump facility.

gulfarea

I was at a very large rv park once and can tell you leaving your gray tank or any  tank open to the sewer means your vent becomes the vent for the whole park! This one man asked me why it smelled so bad near his rig, we walked around his rig in a complete circle and noticed the smell was from him! He closed his open tank and all was well! Art

Sharon_is_SAM

@immanence - the sink/shower P traps and Hepvo valves are designed to prevent gases from entering a home or RV, so it is fine to leave the gray tank valve open (never the black tank as there is no way to block gases from escaping). As @Bayliss said, keep in mind that you will need to rinse your hose after emptying the black tank, so make sure you accumulate enough gray water before departing your campsite.  To continuously drain, I would hook up a standard waste hose rather than using the small hose connection on the waste line cap.  That small hose outlet is designed to drain the tank into a portable waste tank and runs very slowly.

immanence

Hi all, thanks for the great info! I should have clarified that this is a 2021 tab 320 like @kottum noted, so there is no blackwater to leave open just a cassette toilet. 

But given what folks have said about leaving the sewer connections open that is a great point. I will just leave my house attached, but laying on the ground, and empty it when necessary.

I guess one of my main concerns was sticking the hose in the sewer line anyway since that has got to be pretty nasty. I guess I just won't do that! And be careful not to get too close

At least there is no smell here! Probably because we have only been putting greywater down it and leaving it closed.

kottum

If just stopping for the night, I don't even bother draining the grey tank, drain it at the next stop or so down the road.  I do empty the cassette every day and rinse it out, it can get a really nasty odor quickly, even with just liquid if sitting for a day.

As for those with black tanks, I think the odor from your own black tank vent is worse than the odor from the sewer drain.  I don't think you can drain and rinse these too often.

Doug

ScottG

While the various fixture traps should prevent sewer gases from backing up into your camper, there is nothing to prevent them from escaping via the trailer's exterior vent. (This is the situation @gulfarea describes above.)

In addition, in my 2015 the vents for the gray and black tank are connected. As such, campground sewer gases could still theoretically accumulate in your black tank and be vented into your living spaces when you flush the toilet.

I'd vote for keeping the dump valves closed except to occasionally drain the tanks.

AnOldUR

We've only had a site with a sewer hookup once, but the drain pipe was elevated enough so that our slinky worked like a trap. This was unintentional, but I'd think that setting up this way could be done to prevent campground sewer gasses backing up into your tanks.

Sharon_is_SAM

Good point @ScottG.