ATF: Greystone - Gray Water Tanks may not be draining properly

I am concerned that the gray water holding tanks on the 2011 32RL are not draining properly.

This 32RL is situated in an RV park with the gray tank valves always open (per instructions in the owner manual).

The monitor is showing Gray #1 empty and Gray #2 two-thirds (2/3) full.

For troubleshooting, I've closed tank #2 and turned on one at a time all three gray water sources (kitchen sink, bath sink, and shower). I can hear water draining from each source when I close and open tank #1. When I duplicate this method for tank #2, I hear nothing draining from any source.

Aside from a faulty monitor, what might be causing this issue with Tank #2? Shouldn't I hear water draining?

Also, could it be possible that all three gray water sources are connected only through Tank #1?

Clearly, I'm greatly concerned that I'll somehow overfill tank #2 and have no way to drain it.

TX Cowboy, the monitors are notorious for giving false readings, even when new. I would recommend getting a clear plastic elbow to visually check what is coming out of the tanks. You can also use this when you are draining and flushing the black tank to see when it is clear. The kitchen is on one tank and the bathroom, both the sink and shower are on another.

The manual says to leave both gray tank valves open all the time? That's news to me. I only open mine when I need to dump them.

jayc said:

TX Cowboy, the monitors are notorious for giving false readings, even when new. I would recommend getting a clear plastic elbow to visually check what is coming out of the tanks. You can also use this when you are draining and flushing the black tank to see when it is clear. The kitchen is on one tank and the bathroom, both the sink and shower are on another.

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Jay, thanks for the response. I do have the clear (translucent, actually) plastic elbow on the Rhino sewer hose kit. I could see water draining from Tank 1; couldn't see anything from #2.

JohnDar said:

The manual says to leave both gray tank valves open all the time? That's news to me. I only open mine when I need to dump them.

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John, it's there in the owner's manual. It's on page 45 of the version that came with my 32RL under the paragraph entitled "Black Water Holding Tank".

It says: "While camping it is normal to practice to leave your GRAY WATER HOLDING TANK value open if your campsite is equipped with sewer hookup. Never leave the BLACK WATER TANK value open while using the coach..."

Many folks do leave their gray tanks open when camping but we have found that the sewer smell has a tendency to come back up through the open lines. (I know it not supposed to but it does). So we leave them all closed until they need to be emptied. Besides there is always some food particles that get into the galley tank and with the valve open the food particles have will not get flushed out and will build up in the tank and rot. Nothing worse than a rotten food smell. So every 3-5 days you can flush the gray tanks if they need it. The exception to this is when we use the washing machine, I will open the bathroom gray tank so the washing machine water drains. The only time is black tank gets opened is when we drain and flush it.

jmgratz said:

Many folks do leave their gray tanks open when camping but we have found that the sewer smell has a tendency to come back up through the open lines. (I know it not supposed to but it does). So we leave them all closed until they need to be emptied. Besides there is always some food particles that get into the galley tank and with the valve open the food particles have will not get flushed out and will build up in the tank and rot. Nothing worse than a rotten food smell. So every 3-5 days you can flush the gray tanks if they need it. The exception to this is when we use the washing machine, I will open the bathroom gray tank so the washing machine water drains. The only time is black tank gets opened is when we drain and flush it.

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That's how I do it. That also helps flushing out the sewer hose after dumping the black tank since Gray #2 flows like gangbusters. That sentence about leaving it open is buried in my manual, too, now that I look for it. Just because it's in there doesn't make it a wise thing to do. Filling the tank and then letting it fast flow out helps clean the crud out of it. With the very slow flow of Gray #1, I think you're risking a buildup of soap scum, toothpaste, and hair if you let it trickle out. Opening Gray #2 (or even the black tank), then #1 seems to help aspirate #1 to flow faster.

Hey, just wanted to post that I tried what you guys suggestioned and it works great!

Drained and flushed the black water tank (has the internal flush system), closed that value, then opened the grey tanks one at a time. It worked great at flushing the drain hose. Finished the job by running water through the grey tanks for a couple of minutes then closing all of the values.

Thanks for the suggestions!