If you put pond water in a res your going to grow a lot more than weed. I'm sorry I forgot about the filter.
I'm glad you asked this question, I too have a pond and was told to stay away from it for indoor growing. But I used to work at building water treatment plants. Installing filters was one of my jobs. So if your interested you could build a mini version of one with a 55 gallon drum. First drill a hole and install a buckhead then add a horizontal pick up ( pic pipe with holes drilled in it wrapped in landscape cloth ) next layer stones in progressive smaller size finally topped off with sand. Pump water over the sand when it comes out the bottom it will be free of sediment. Put that water in a tank with a uv filter. Probably ok to drink. Idk if this helps but if you try it I want to know. Peace out Bare
