I tried a 10 gallon blue portable tank for awhile. Partially emptying a 25 gallon grey water tank, or the 15 gallon black water tank, into a 10 gallon blue tank takes some careful monitoring, even with the little pop-up thingy. Obviously, you can't dump the full tank. The low end of the sewer exit on my 17SD does not help much either. Hooking up to the back end of my 4Runner was not a big problem, dumping and lifting the tank was not so much fun. In the end it was more work than expected and I gave my blue tank away. I mark my desert spot with chairs, carpet and what have you and have gone back to regular dumping. Some parks allow grey water dumping - if it's allowed I switch to biodegradable soap. Also, I've added a strainer in my sink, this traps almost all food scraps. I tip and empty the strainer into the garbage can multiple times a day. I found my grey water smells less since.
A fun memory from about eight years ago. I was parked in Pancho Villa State park. The manager allowed grey water dumping (it's a bone dry desert after all). I ran my hose into a bush. To my surprise, within days Gambel Quail came by every afternoon to flap their wings and move about in the soft moist earth before retiring for the evening.
ps: I often forget to check the date of the original post. It may well be that the original poster has switched to a 45ft motorhome or has moved to Timbuctoo. Hope my post still has some value.
Edited by Dutchman, 29 August 2018 - 05:09 PM.