Canister is on the floor as it is. The base of the reactor is 2 inches or so above the canister.
If I fill it up half way, I will simply have an impossibly large air bubble to fight. The water in the reactor will drain into the canister, but no more, after re-attaching the disconnect for the hoses. Unless I am missing something there. Priming results in no "gush" of water. I had to prime the unit so many times last time my hand was tingling for 3 hours afterwards and I had a blister develop.
anyway for you to take a picture of the setup?