Originally Posted by
AquaticNerd
When you say resin, I assume you're talking about DI resin for an RO/DI system (since that's what I believe you've spoken about in posts elsewhere). Whenever I've used DI resin, I usually just give the cartridge a few hits on the table to make sure everything is settled without large empty spaces, otherwise I've filled it to the brim without leaving any additional space. I haven't "packed" it like you would pack brown sugar when baking. The whole idea of filling it completely without extra space is that you prevent channelling - water won't make a natural channel in the DI resin where it can bypass the resin completely leaving you with non-DI water as it makes its way through the system.