I've been ponding for about 20 years all together, my present pond is our second after we moved out to the country. My wife talked me into building one that's a bit too big and a bit hard to maintain. The pond is about 38 feet long and about 18 feet wide, 4 1/2 ish feet deep to 2 1/2 feet deep and unless my calculations are whacked about 11,000 gallons. We had a waterfall that I never really was quite satisfied with, feed by two pumps in the bottom of the deep end and a skimmer in the shallow side aided by the prevailing winds. After about 5 years of use, last year we had a leak of about a 1,000 gallons a week. I took out all of the rocks in the pond as the water slowly receded looking for what I assumed would be a fairly obvious tear in the liner. During this process we set up a swimming pool to house to house the fish and transferred at least 200 comets that started out as a dozen feeder and 5 frogs. It sooner became obvious that the leak was else where, but I kept going because there was an unbelievable amount of muck. With the waterfall shut down the water level stabilized, so after a complete clean out of the pond, we added water and transferred the fish back to the pond for the winter. Right now water has gone pea-soup and the fish aren't feeding vigorously while we're limping along with inadequate filtration. I'm upgrading my filter-fall as it had a large leak last year. I'm rebuilding and repumbing to allow dual 2500GPH pumps on the bottom, check valves in case one pump goes out and a venturi aerator, going through 3 inches of green Matula filter, then 50 L of K1 and the exit the 23 inch wide weir. The filter-fall is going to be built on a piece of EDPM liner so if there is another leak we don't lose a thousand gallons a week of water. We have a skimmer in the North-East conner of the pond as that's where the prevailing winds push the flotsam. The pond has a waist in the middle which causes conter-rotating gyres separating the pond into an east and west half. I intend to place a venturi aerator at the waist in hopes of getting the gyres to merge into a whole pond circulation. In the past protein frothing from the water fall has been sucked into the skimmer when the winds were favorable and I would be happier if that occurred continuously; if the venturi doesn't do it, I'll add a second skimmer in the west half on the north side to skim any flotsam that doesn't make it to the east half. The skimmer on the East half has a 2000 GPM pump attached but the flow rate is restricted due to using 1 inch irrigation tubing to connect to the Bioclear 5 over by the waterfall. I'm going to replace the inch pipe with 1.5 inch PVC. If the flow rate overwhelm the bioclear I'll hook up something in parallel.