Hi all - wow thank you for the input! For some reason a few of these comments never made it to me via email, so sorry for the delay in response. CHAS: I think I'm going to just go with a shorter stream, which will cut down on the height a great deal. I will wrap it around the pond (instead of going straight up the sloped ground) - which will make the head height less and also keep the flow calmer for froggies. I also decided that I will focus the main pond on fish; and I'm going to put a little, shallower pond tucked along the creek which will be just for frogs - with a pump maybe, but no filter or anything (my current frog pond has just a pump/waterfall, no filter, and the frogs are very happy and healthy there). Hopefully the frogs will natuarlly choose the little pond instead of the bigger pond, and even if they lay eggs in the lower pond, I can just move them up to the froggie pond. I at least will feel like I've done my part to provide a safe haven for them :) RSINGLEY: I had read a similar recommendation elsewhere of putting mesh and other media around the pump - I like the idea, though I do wonder what the negative effect of not filtering the larger particles will be? (seems silly to get a debris handling pump and then restrict the debris from getting in, but alas, the dilemma of tadpole lovers). FROGMAN4: You'd be right on the calculation but it's not all at a 3.5' depth, and it's an oval pond. If you picture an upside down oval wedding cake: the biggest layer is 16x13 but it's only about a half-foot deep (it's a rock shelf). The second layer is 14x11 and is 1 foot deep. The third layer is 11x8 and is 2 feet deep (so total depth at the bottom will be 3.5). I calculated each "layer" out as separate pond volumes; using the oval pond forumla of L x W x D x 6.7, the top layer is 696 gallons, 2nd layer is 1031, 3rd layer is 1179 = 2906 gallons. The third (bottom) layer will have sloped walls, too, which actually will cut down the gallons, but I'm fine with over-estimating. I have wavered back and forth a hundred times about going with a skimmer filter as opposed to an external mechanical filter. I still haven't hit the "place order" button on my pump/filter order, but I made up my mind last night that I was going to go with a Laguna max flow pump (2000 gal), pressurized filter (3200), and also have a waterfall bio filter at the top. Holding off on the drain for now, but I saw some that I can add later if the need warrants. Chose the external filter instead of skimmer because I didn't want to have to do 2 pumps, and I just felt that not having the pump at the bottom (which it wouldn't be if I put the pump in the skimmer) wasn't the best idea... which was my deciding factor. I hope what I'm choosing will be sufficient... weeks of research got me here, and I'm ready to just install all this already! :) MEGANMCA: Thanks for that link - it's very helpful! I did read that pipe diameter is important - I'm going to go with 1.5" and hope that's sufficient. My sister just installed the same pump/filter combo I'm using with 1.5" and it's a beatuful flow. Her waterfall is a little lower than mine, but I think it will suffice... If not, can add a 2nd pump but hoping I don't have to do that. Thank you all so much for the input - and as always open to any other thoughts/suggestions!

Thanks, Gilroy! I wonder if anyone has success posting images from their libraries directly to gardenweb? We've gone back and forth--from making the pond into a firepit--which would mean somehow making it drain snow melt and rainwater, to reviving the pond, which means a bigger financial and time committment, plus lots more to learn (just trying to figure out the GPH and the lift and the head height and immersible vs external and direct drives vs mag drives...! Yikes!) We've also talked about making it a firepit surrounded by a pond or somehow making it into a hot tub or outdoor pizza oven. It's the focal point of our backyard and letting it fill up with algae and Mosquitos and weeds every summer just isn't working. Our neighbor put in a swimming pool and all the noisy equipment sits atop the hill just above the pond's retaining wall and behind a hideous chain link fence. We're hoping to cover up the noise with the waterfall sounds and eventually put up our own wooden fence to hide the chain link. But, wow, what a lot of work and expense. I love old houses and am glad you're trying to stay true to the design of your home's era. Have you posted any photos of your home and where the pond is sited in relation to the house? Good luck!

A filter is the easiest and most effective way to keep the pond clear. Floating or stem plants will help but fish do best with a filter especially if it is more than a couple. If you cover the water with floating plants than the water should stay relatively clear and on the good side you do not really see the water that way. once you get a filter going the water should start to clear fairly quickly, couple weeks. If there are no fish or plants than dosing with an algicide will get rid of it for a while, but only if there are no fish plants and read the label to ensure that critters passing thru that take a drink won't be hurt

Okay, I figured it out. The filter needs to be installed after the pump so the water is being pushed through. That would solve my problems.