Stop doing water changes and leave the filter alone! You are making the situation worse every time you replace the water and clean the filter.
Do a search here for threads about green water.There is lots of information on how other pond keepers got over the new pond (Green water) syndrome.
"Horton"

Lakesuperiorgirl, check out the link below.
There is lots to read on the subject.
The biggest thing is to have patience and let the pond cycle.
"Horton"

Here is a link that might be useful: Green water threads.

Personally I have tried and do not like pressure filters. They take way too much water to backflush and rinse the media IMHO and if your source water is high in phosphates, or chloramines then you are courting trouble. Horton gives good advice as usual. Also do you have fish? Do you fertilize the lilies?

BTW- Your pond is absolutely lovely!

Lisa

Thank you, Lisa. Horton, I am confused; don't I need to rinse the gunk out of the filter in the skimmer? I used a piece of air conditioner filter. It gets full of the algae, so I thought I needed to rinse this out. I don't have pea green soup and the water has the blue hue as I added a colorant. I just have the gunk on the bottom, some bright green algae in the falls and around the bottom of the hand pump where the water hits the surface of the pond. I clean this when it gets too much with a toilet brush. When I clean the pressurized filter (about every two weeks) I rinse the filter pads with a hose and the bio balls I leave inside the tank and rinse with pond water by just sloshing it around some and dump it out (no fresh water hits these). I have well water. I have 2 5-6inch koi, 12 3-4 inch feeder goldfish. I don't feed the fish but maybe one a week and it is only a pinch. There should be enough larvae, etc for them to eat in the pond. I am more wondering about the crud drifting on the bottom. Thanks for all the help.

LSG, Got it now, sorry I had it in my head you were dealing with green water.
The "stuff" on the bottom is algae and debris from fish food/waste. I see you have rocks on the bottom of your pond. That can become a bit of a problem, as all the junk settles down between the stones and can cause all sorts of nasty situations. It can become a breeding ground for parasites and disease in a garden pond.
A bare pond bottom is easier to keep clean, by netting out the accumulated junk.
Never clean off the sides of your pond though as the "good" bacteria colonizes there.

As Goodkarma pointed out bead filters take a lot of pump pressure to work effectively and that maybe part of the problem also.
You should continue on cleaning that filter pad in your skimmer as it is actually a mechanical filter which is picking trapping some of the solid waste.
"Horton"