Can I tie two gray tanks together?

[Steve & Katey]

They do make a glue on version. What I do though is put the handle portion to the right which gives extra weight and force to keep the bayonet fitting trying to tighten on vs loosen. So far no problems.

Yup! Just bought one for that purpose. However, don't really like the twist-on fitting all that well - seems like it could come loose. Do most take it off when traveling or make it more permanent somehow (i.e. with adhesive or silicone)?

[Malco1]

I would like to increase the capacity of my shower gray tank by tying it to the kitchen tank. Is that possible or not recommend?

I tried combining the tanks by opening both gray tanks with the Valtera gate valve closed and it didn't work. Both times the bathroom tank filled up and no water was let into the kitchen tank. Maybe if the kitchen tank fills up it may flow into the bathroom tank, but not visa versa at least in my rig.

[huntindog]

I tried combining the tanks by opening both gray tanks with the Valtera gate valve closed and it didn't work. Both times the bathroom tank filled up and no water was let into the kitchen tank. Maybe if the kitchen tank fills up it may flow into the bathroom tank, but not visa versa at least in my rig.

All that means is that the bathroom tank is lower. If you contued to use it, water will end up in the kitchen tank

[CoChris]

I tried combining the tanks by opening both gray tanks with the Valtera gate valve closed and it didn't work. Both times the bathroom tank filled up and no water was let into the kitchen tank. Maybe if the kitchen tank fills up it may flow into the bathroom tank, but not visa versa at least in my rig.

In a Solitude 310Gk, the bathroom grey (and black) tank sit in the drop down frame (below the passthrough) and is at least 10" lower then the kitchen grey tank.

Chris

[fez111]

I would love to connect the two gray tanks on our 2250rk, but they have separate dump outlets and an axle between them. We always fill up the shower gray, but never come close to 1/4 or 1/3 on the kitchen gray. We got one of those 28gal rolling totes to dump during stays, but would prefer to connect the tanks if possible. I was thinking we'd have to run PVC from the shower gray to the kitchen gray and have it slightly downhill.

I connected the two tanks on our previous Rockwood 5er. On that one the axle was under a square tubing that ran between the frame and the axles. I managed to get a piece of 1-1/4 inch PVC inside that square tubing. The front tank outlet had a large hose clamp holding the equivalent of a 3inch PVC pipe reducer which I swapped out for a real 3 inch pipe reducer down to 1-1/4 inch. I connected the reducer to my pipe that was run through the square tubing. On the other end I tee'd into the outlet pipe for the other tank, upstream of the dump valve. Voila! 80+ gallons capacity of grey water.

One caveat... Because the elevation of the pipe between the two tanks was higher that the dump valve, I had to tee-in a drain on both sides of the axles for winterization. Even so, having the extra capacity was worth all of the trouble. We never use the RV shower at public campgrounds so that tanks was just wasting space.

[lfytsmith]

I think that is the same model that Jared (All about RV's) on YouTube did that combine. Might check his video out - https://www.youtube.com/watch?v=tstF9odI0RE

[Yosemiteman]

I think most of the options and variables have been discussed. On our 303RLS both gray tanks are at the same elevation and connected to the same dump exit. I was able to cut off the existing sewer cap fitting and glue on the 3' Valterra T50 bayonet valve with integral sewer cap in as shown in the attached picture. Works great. I use it to equalize the gray tanks at times and also to flush the emptied black tank at the dump station station.

[ajg617]

I tried combining the tanks by opening both gray tanks with the Valtera gate valve closed and it didn't work. Both times the bathroom tank filled up and no water was let into the kitchen tank. Maybe if the kitchen tank fills up it may flow into the bathroom tank, but not visa versa at least in my rig.

Glad I read this before I tried it - our bathroom tank does fill up much faster than the kitchen tank.