Pics..HELP!

hey everyone.. i was wondering if you could take a look at these pics i just
took of my pond.
http://thenyscene.com/pond/1.htm

last year i had the same problem... green water.
I have narrowed it down to the following possible problems:
- Too much water flow
- Not enough water flow
- Not enough plants (although its only april here.. and still goes down to
the freezing point at night)
- The pump is too close the bottom (collects muck and spreads it through
out the pond)
- Not enough shade

any words of advice?? thanx!!!!
John