Dump Valve Modifications

I've read here before that some folks have combined the two drain lines into one dump valve, thus to ease the dumping to one stop. FWIW, I've never owned a trailer before that had a dump, so it's a new chore for me.
I'm no pro plumber but I always do my own and plumbed each house I've built so really looking for how to avoid a pitfall here, not the basic piping procedures. I looked at the two drains and would seem obvious the gray water would need to run forward to the black drain pipe, which is larger. My Model 177 has axle risers so there appears to be plenty of room to make a drain pipe run forward. Slope is a concern that I don't know how to deal with here? Ideas?
I tried the search function on this and gave up on terms to describe this modification!
Thanks in advance! Mike

The R-pod has one flex hose in the tube mounted under my battery (I assume so because I've never opened the tube, as yet) but with this Camco "Y" fitting, as shown in your Walmart link, you need two flex sewer hoses. Where does the 2nd hose get stored? Can two hoses cram into that tube?
FWIW, I'm a skilled trades gut but obviously a greenhorn on this dumping thing!
Thanks for your time in reply!

Originally posted by Kantuckid The R-pod has one flex hose in the tube mounted under my battery (I assume so because I've never opened the tube, as yet) but with this Camco "Y" fitting, as shown in your Walmart link, you need two flex sewer hoses. Where does the 2nd hose get stored? Can two hoses cram into that tube? FWIW, I'm a skilled trades gut but obviously a greenhorn on this dumping thing! Thanks for your time in reply!

I would look at the storage tube. Mine did not come with a hose. The only length that will fit is a 10' length. I found out when I had purchased a 15' hose and tried to fit it in there.  If yours came with a hose, I would be surprised.

You can purchase hose and fittings separately. That way, you could make two short hoses to the wye. The longer hose could fit in the carrier and you could either leave the short hoses and wye (with a cap) connected, or take them off and put them in a plastic box. I store the elbow and my hose that is used for the black water flush in one to keep them separate from my fresh water hose and filter.

Okay. I didn't know you had purchased it used. In that case, it is likely that there is a hose in the tube. That will save you some money. It really isn't hard to move the hose between the black and gray water connectors as needed. I also carry a box of nitrile gloves (from Harbor Freight) to handle the hose. I then peel the gloves off and throw them away. That keeps any potential drips from the black water tank off of my hands.