I see what you are saying now. It makes sense. I've noticed the water level in the reservoir has dropped, while the level in the bog has stayed up to the drainage holes. Either way, works or doesn't it will make it MUCH easier for me to fill the bog back up when the water level drops. I was having problems previously keeping the water level up. The media was absorbing the water way too slow, I would have been out there all day trying to water it.
The water level in the PVC pipe does not match the over all water level of the bog. What I mean by this is, dig down 3" and you hit water. The water level in the PVC pipe (leading down into the reservoir) is about 6-12" lower.