I have used small blumats in large 35 gallon pots with over 15 inches of depth. The secret is to move the drip line closer the deeper the pot gets. Otherwise you will have runaway issues. I use 10 distribution drippers and 2 small blumats per 35 gallon container.Oh sweet so those are the longer one than huh? I just have the normal ones. I'm slowly getting into ROLS too and will be getting 15 gallon pots soon too. Do you think two of the small ones for 15 would work ok or does a pot that big need the max ones that you have?