The average adult colon is approximately 5 feet long and 3-1/2 inches in diameter at its largest point...the cecum. And that is IF it is a healthy colon with no ballooning and no history of impaction which can cause it to stretch considerably. There is no possible way that the quantity of liquid that you've indicated would even come close to spanning the entire surface area of the colon...which could only happen IF it was completely emptied...and a standard 2 quart enema won't even do that!
As I said...I'm not disputing that you have derived benefit from this procedure...but there is no possible way that it is reaching the entire colon.