Here is another idea . You can buy the part to accept the piece of hose then be inventive . I know a piece of three eights copper tube will fit in the open end of the hose . The rest would depend on your knowledge and understanding of terms for me o go further . No offense but I think you are pretty green. Get the hose take it to the hardware store that an experienced person works or better yet a dedicated plumbing outlet. Take your rodi with you or if the instructions
are clear as to the inlet size take that . the rodi would be better. Anything is doable. The tubing that goes inside the hose will be sealed by gear clamps . If you can find the type of fitting as above on the right your set. Just mount your Rodi by the laundry tub , and only hook it up when you use it. That way mom and dad will be happy