As I noted above, increasing flow only resulted in the fill time getting as low as 10 minutes. However, the drain simply accounts for this by increasing discharge to match the flow, though the reaction is a bit delayed.

Increasing flow, and reducing the M to 1/2 inch, simply increased how much faster the barrel filled, and dramatically reduced how fast it drained. This makes the barrel over fill, and if no action is taken overflows.

jvision --am I understanding then that you are filling with a 1 inch reduced to 3/4, and draining with a 1 inch? I am starting to think that this is where my error is. Filling and draining with 3/4 just isn't working, even with ball valves on each barrel, I simply am unable to match what is needed.

If it drains faster, the suction will break in time due to lack of water not filling the pipe. A 1" pipe will take more water to start siphon, there by requiring the water level to be higher in the barrel before starting. Okay, that sounds more like of what I am needing. Looks like I am going to have sacrifice one barrel plug, and make yet another hardware store run for the 1 inch parts. I will start this time with a simple loop or N. And then convert to the M and compare the differences.