Just joined today and had a response as to where to find the media. Wiegand's Nursery. on Romeo Plank Road north of 21 Mile Road has media in a roll. Bring in one of your pads and they can cut to size. They have different sizes and thickneses. I will be doing soon just to have a spare set when the time comes.
As to the pre-filter that you have been using...what material is screening the water? How far is it from the front of the skimmer (so that it doesn't restrict the flow?) Any info you could provide would be appreciated. We have been struggling with our pond and just can't seem to get the water quality where it should be. Just changed out about 2/3 of the water yesterday, cleaned the pads, vacuumed the rocks (bottom and shelves) and put in new bacteria. Water was getting green - no string algae at all. I have 6 koi (1 larger and 5 smaller). Was concerned that we couldn't even see the fish for the green water, but everything is looking up since the cleanup yesterday. Just want to stay on the right track and try to let nature take its course. Will continue with the bacteria weekly, and the muck control, but try to keep away from the other things we put in the pond - like algae control, Insta-fix, etc. Nothing would be better than to have it all done naturally. It really is potentially a gorgeous pond.