jclimber, I've have a setup very similar to what you are talking about though my pond is only half the size, still large for an ornamental pond with goldfish. I have a Savio Skimmer with two pumps, one goes to a rapids effect at a small, small stream that feeds in under the biofilter fall, and, the other one pumps into the biofilter. I also have an upper pool and a lower pool separated by a wide but short water fall. The Savio Skimmer (full size) is located at the other end of the lower pool from the waterfall. My two magdrive pumps work fine. Laguna brand 3900 waterfall pumps. That all said, I would take ccoombs advice, no doubt. The number one problem with my pond is keeping the detritus and other junk off the bottom. In fact, you never can keep it off the bottom. The detritus is so fine that you only stir-it up if you get in to clean the pond. So my advice would be to go with the bottom drain setup but still use a skimmer box for the top floating stuff. Thanks for the btm drn link, ccoombs; I hadn't seen that... and thanks for the explanation of the bottom drain (not for draining, necessarily) because when I first heard about BDs that what I thought for sometime! I like the suggestions for saving money. If you can afford the time, better to make your own... esp. underlayment; I actually think old carpet (go dumpster diving at a carpet store) is superior to the underlayments I've laid hands on. Here's another suggestion: I'd get the rock out. It would be one thing if they were in the water atop the liner, but rolling liner up over them is just taking up space. Plus, you could use those big ones to help landscape at the edge. So it occurred to me when you talked about getting an electrician to bring a circuit out to the pond that this electrician is going to have to pay someone to trench. Most places are under the National Electric Code and that means burying the cable 30" or more... they're going to want to use a trencher. If you're going to have to get a trencher in for that you could save by getting a mini-excavator (rental from any tool/equip rental shop) and have it equipped with multiple bucket sizes... most come with options. get a slender bucket for the trench work, wider bucket for the rock. If an excavator can't lift the rock it should be able to beat on it enough to crack it smaller and scoop it out... of course, you could just pay someone to remove the large rocks. Whatever you decide make sure you have 'em mark the area for underground utilities. I really like your setup though. You never did say if you planned to have fish, what kind? Is that a german sheppard!? He/She will love the pond!

Well it's Kansas so it will stop raining just before the drought begins. ;) Like pondmanimal said, check for the leak. I found my pond leaking at the interface between a plumbing pipe and the liner. Do you have any plumbing (pipes) in use at the pond? I would think to look there first. But the water between the liners might be a liner leak. The owner of my local pond store has years of experience with sales and installation of ponds. She told me that if you can afford to, shut off the pumps and see what happens over time. I guess if the pond stops leaking during the shutdown then you know the leak is in the plumbing. That sorta worked for me.

I did pipe boot connections on my retrodrain through the wall of the pond. Didn't make my hole as large as what Horton suggested--only 1/2 the diameter of whatever size pipe. Most recent was 3" and made a 1 1/2" hole in the centre of where I wanted the pipe. The liner stretches but it takes strong fingers. Easy to do and as far as I know no leaks. Curious why aren't you looking at external pumps for your pond? They are more energy efficient, easy to winterize. I have a priming pot on both of mine even though they are below ground but had a problem with quilt batting getting wrapped around the impeller of the older pump before using a priming pot. I have a Sequel 4350GPH pump that is very quiet uses 175W. This year I plumbed this pump to my sc and the old pump (Sequence 750 4200GPH but only pumping about 1/2 of that due to bent shaft) to my skimmer. I probably don't need both pumps as also changed my waterfall out this year so is smaller. The Sequence is noisy and leaks a little on start up around the shaft. Long story short I love the external pumps. Aquaart carries good external pumps and also the bottom drain that is mentioned either here or other forums. I also like the skimmer--it collects alot of surface stuff like dust! In the fall I run my pond on the skimmer only so that I can remove my drains (have a midwater drain now which is also awesome) before the water gets too cold. Like Horton my pumps/sc are hidden under a deck. Two pummps might be an idea for your pond as you need less flow through your biofilter and more flow through your waterfall. One idea I saw here if you only use one pump and need the circulation (in your case at least 5000GPH) was to pump part of the water back into the main pond and the rest through the biofilter/stream. Aquaart has a diagram of how to do this. As for valves depends on if you have a drain on you skippy filter etc. I have a knife valve between pond and sc on the bd but on the midwater drain which also goes into sc I don''t--I use a standpipe. After skimmer and sc 2" ball valves--I know could have used knife valves there but ball valves are more reliable. My check valves are after the pump but before the ball valves to the waterfall filters. This is to keep the water from the waterfall filters coming back down through the pump and into the pond if power goes off which it does here frequently. Because I have priming pots, sc and skimmer I don't need check valve before the pump. Can't remember when you need check valve before the pump--sorry. Ball valves after the check valves to control flow to filters. I know that I could get away with running one pump now due to the changes I made in adding a midwater drain to my sc (had alot of draw down!) and waterfall changes as the valve on my Sequel pump to higher waterfall is turned down more than 1/3rd. It's just time consuming and more pipe to change it out again. I don't know if you are allowed to use ABS in the US. I use it here as fittings are available and it stands up to my climate. Also because it's black any pipework in the pond lie retro bd don't show as much. You have a fun project on your hands! It can get rather overwhelming but there are many knowledgable people on this forum who can help you. Good luck. Patti

In response to your first question concerning the pump. What you didn't mention is the performance of the pump at different head, i.e. how much water flow does it deliver at the highest point. You also need to calculate the head loss of the piping/plumbing you use. Most pumps (at least here in the states) include a chart showing the pumps capacity at various head levels. Also keep in mind that head is measured from the water surface and not ground level. Question 2. Koi and goldfish love a strong current in the pond as long as they have some little area they can go to rest. They will often be found playing in the strong currents from a waterfall or under water return. Question 3. Koi and goldfish are "coldwater" fish and will survive winters just fine as long as you keep a small hole in the ice and the water in the pond doesn't freeze solid. They may appears listless or dead in the spring but as the water warms they almost always come. I think your pond is deep enough that you won't have to worry, especially if you keep a tank heater (like the ones farmers use it stock tanks) in the pond in winter. 4: I would use goldfish and not too many. Koi will get big and make a lot more waste than the goldfish. Oh, and don't use the "fancy" goldfish as they are not as hardy as the regular ones. 5: You can go either way on this one. Some people I know turn their pumps off other (like me) keep them running year round. The main issue is to keep enough oxygen in the water for the fish. In any event with your winters I would put in a waterfall bypass and return the water directly to the pond and not use the waterfall during the winter. Running water in the waterfall during the winter is a request for disaster. The water will gradually freeze and often will cause the water to escape the confines of the normal water column resulting in a drained pond and lost fish. 6: Just keep the pump running to keep the water oxygenated. 7: I am not an advocate of putting gravel in the bottom of a pond. It is a recipe for disaster if you have fish. All the fish waste gets in and under the gravel and it is very hard to keep it clean. This results in a layer of nasty bacteria beneath the gravel which will eventually be harmful, even fatal, to your fish. A gravel less bottom makes cleanup easy There are a lot of aquatic plants that will grow in your environment. you can use marginals and set them on the "steps" and maybe one hardy water lily in the deep or next step up. Floating plants do will in a pond as well. Of course this all depends on how much sun the pond will get. DO NOT use any "potting soil" in the pond. You can plant most plants in pea gravel and they will do fine. Some people use regular old clay soil with nothing added but I find that the fish like to dig in it and then it gets all over the place and the plants end up floating out of the pots. I'm sure you will get lots of good advise from the users of this forum. everyone here is very helpful and knowledgeable. Best wishes on your journey into ponding.