I just started a duck pond with a 6' diameter x 2' deep (400+ gallons) stock tank with a 95 gallon stock tank that will be used as a Skippy filter. I had to put the output from the filter lower than I'd wanted due to the design of my Southern States (versus Rubbermaid) stock tank- the flat side had a ridge close to the top so I couldn't put the flange as high as I would have liked. I have ten 17" commercial floor scrubber pads inside for filter media, and the back portion is empty for eventual water plants. I had a sump pump I bought at Harbor Freight that I'd intended to use as my pond pump, but read about all the negative aspects of using one here and in other sources, so I ordered a Tetra Debris Handling pump rated for 3000 gallons. We'll see... I bought the big stock tank a few years back (stopped using it when a chicken fell in and drowned later that season... terrible but I think it was a fluke) that probably cost about $250, and beyond that I have $75 in the smaller stock tank, $25 in floor scrubber pads, $125 for the pump, $13 for an egg crate light grate, probably about $30 in random PVC stuff, about $100 in really heavy duty extension cords, since it's about 150' from the house... I'm sure there's more I can't think of right now, so it's not going to be cheap, but all in all I think it's going to work out pretty well and it'll be way cheaper if this setup works from the start. (I keep thinking of when I first got chickens, and started out with an Eglu for my two that became 5... then "upgraded" to some other ridiculously overpriced and poorly designed coop and run, then finally went out and bought a Lowe's plastic shed for a couple hundred, made panels out of 2x4s and 1/2" hardware cloth and a roof out of corrugated plastic roofing panels for the attached run, and finally had a winner. Just how much these eggs have cost me each will forever be incalculable.) I just got the pump and filter running last night. Here's what the current setup looks like: I put sticks and branches around the mound to keep the chickens from scratching it all away and the ducks from grabbing (as much) mud and dabbling it into the pond. As I acquire rocks, they will be placed on the mound all the way around the pond. My grandfather has a large (20 x 40' +) ornamental pond in his yard, and tons of anacharis and duckweed growing in it. I'm going to steal some this weekend and throw it in the back of the filter to eat the nutrients from the water, and feed excess to the duckies.