Ron:
Welcome to PB! It was asked before, but I'll ask again. What are your goals for the pond? If fishing, what do you want to catch? Swimming? Wildlife attraction?
I have a feeling you'll be spending more than a few hours reading here, and in the archives.
If possible, take a look at how to
post photos here on the forum, and take clear close-up photos of the weeds/grass that you want to reduce in the pond. With the water flowing thru the pond, it might be hard to keep a plankton bloom going - the nutrients that those little buggers need will be washing out of the pond, minute by minute. While that may seem to be a bad thing, I think it will help you by helping to eliminate the normal Filamentous Algae (FA) problem that most small pond owners have (yours truly included). If you have a hard time keeping a bloom going, you can always add fertilizer that is especially formulated for ponds. I bought mine from Greg, although he's not the only supplier. I just feel that if a person is going to be kind enough to give me free advice, and they happen to sell a product that I can use, I try to repay their kindness by doing business with them.
If you can take pics of the fish as well, we can identify them for you. Good side views are nice.
There are biologists, pond specialists and general pond owners here. A few comedians as well, just don't pay any attention to them, and any glorifying that they spew about GSF (Green Sunfish).

JHAP, I just donned the tin foil hat so I'm ready for ya!
You are in good hands here, changes won't happen overnight and you'll soon see why "it depends" rings true for so many situations.
What have you done on The Discovery Channel? It gets watched frequently in this house.
You'll see a lot of acronyms used, here's a
link to what they stand for.
Stay tuned, the ride has just begun!
