would help to know which spot is causing you the problems when looking at the photos.

If I am seeing this correctly you have it setup for the following.

Back left corner looks like you have a filter/pump that will pump water over the ledge/waterfall and down into the pool on the from left. This will fill up and run along the front of the tank down into the lower pond on the right side. This in turn leads back across the back of the tank to the filter in the back left.... I think I am right, but please let me know or correct me if I am wrong.

What I can't see is the area that is causing you problems.

Don't get discouraged This is all part of the process. We all go through it at one point or another. I had a tank where I had to totally abandon my water feature idea because I couldn't get it right, but I learned from that build and have had some success (and more failures) on tanks since. I don't think this is something that needs to be a tank killer. We can beat this thing!