Is it possible to have a watergarden pump that is too powerful?

Question:I have a watergarden that is around 800 gallons (11' x 6' x 1.5 appx). It seems the best pumps and filters use 2000 gph pump. Isn't this too much? I live in Florida and the pond easily gets 6 hours of sun. I'm new to this and the more I read, the more confused I get! I recently looked into a skimmer/filter system but now i'm looking at a waterfall/filter system, as it seems better. The pump I have is 535gph and it has a fountain attachment. I'm going to add fish eventually. And am I right that the pump just attaches to the waterfall with tubing?

Answers:
Yes, the pump attaches to the waterfall with the tubing.

Theoretical, you will be able to pump all of the water through your pump every hour and a half. However, the diameter of the tubing will most likely REDUCE the amount of water that can actually be pumped. Also, if you have to pump the water UPHILL to get to the top of the waterfall and the further away the waterfall is, the less that will actually get pumped. Make sense?

Good Luck!!