Peggie, I'm wondering just how the head (Jabsco manual) works. So, I switch it on 'dry' bowl and pump. As long as I pump is the waste moving through the hose toward the tank or is it just lying in the hose (similar to house plumbing) and requires water to move it further along (I assume that is the case) , which means that more 'wet' bowl pumping is required. I use your method of conserving holding tank space by pumping 'dry' bowl first (talkin #1 here..) then about three or four 'wet' bowl pumps then back to 'dry' for three or four more pumps. Does the 'wet' bowl setting draw water on both the up and down stroke? Should one cycle of a 'wet' bowl pump count as two pumps or just one pump? We seem to be almost filling our 13 gal. holding tank in just 2-3 days so we pump out relatively often. Maybe we're pumping to much water? Thanks. Tom M.