http://www.enemabag.com

Don't Worry,

The only thing that counts is how your tummy feels. I use a four liter bucket, rarely do I take it all. The reason people like it to be clear is the fact that it adds to the moment to see the solution flowing. It does serve as a guage to tell you where you are in the proceedure, but is not necessary. I can't see my bucket, I just listen to my tummy and generally take three liters or so.

It's nice to know the amount of water your using indeed. The clear bag method is the way to go unless you want to fiddle around with measuring for each application in a series of successive enemas.