Wow, Albert. I hope you weren't expecting an answer in just twenty minutes. I just logged in at 4pm and your post is at the top of the list so I would guess that by 6pm my time you will be getting some answers. Maybe I just read you wrong. I'm in a really bad mood today. I logged in to cheer myself up. The thing is that there are so very many sources and they all appeal to different ponders. There are so-o-o-o many ponds and so many personal preferences. No two ponds are alike. I must have looked at a hundred sources in the many years I was just dreaming. Most of them had some good ideas, some were obviously written by someone who had no real experience at all. You catch on to those in a hurry. There are some basics that should be followed and I will list a few. I'm sure others will have additional advice. Your area may have zoning restrictions. Check it out. I can't imagine having to fill in my pond for lack of a permit. The next thing to consider is location. A higher spot is preferable to a low spot. This prevents runoff containing chemicals from getting into the pond. It also prevents ground water from interfering with the liner. Drainage can be critical in some cases. Accidentally flooding a neighbors driveway due to an icing problem is not a good thing especially if it could have been avoided. It is better to site the pond away from deciduous trees to reduce maintenance and possible intrusion from roots. Leaves mess up everything to do with the pond but sometimes it is unavoidable. The pond should be located where it is in good viewing range for pleasure and safety. It needs to be accessible for safety and maintenance and access to electricity and water. The size of the pond is determined by many factors. If you want to have fish as permanent residents they need a particular amount of oxygen rich water for good health. A lot of fish mean larger pond size and fish grow and reproduce. Koi need more space than the comet family. They need a depth of at least three feet somewhere for exercise, protection from predators, winter cold(ice cover)and summer heat. Many if not most ponders discover they wish their pond was larger. This can get out of hand if you don't have enough experience before you dig your final pond. Starting small and cheap is no disgrace. Too small and you may be starting over. My 10 year old pond is 1000 gallons, approximately 10 feet by 10 feet. Yes, I wish it was larger, but I am too old to indulge. I will play with details. Pond shape is personal preference. Some people like geometric shapes, some prefer more natural shapes. If there is a ponding community that has a tour near you, take it. You may find your own preference is different from what you expect and may get some great ideas for your area. Digging the hole...Well, if you have a spouse like mine, you can dig it yourself by hand if it is only a moderate size. It took me most of a summer, but then I am 5 feet tall and had flaming fibromyalgia and could only do it a little bit at a time. It does make the hole very personal. Those who have access to more hands or motorized equipment can do it over a weekend. Liners are expensive and going cheap can create problems. There are all sorts of possibilities but a majority on this forum seem to go with .45mill EPDM, which is rubber sheeting made almost exclusively by Goodyear. There is no proven difference between that sold for ponds and that sold for roofing material although some are leery of the roofing stuff. Some roofing material is treated for resistance to moss and algae. It is not appropriate for ponds. Check the prices and availability in your area. Sizes vary and larger sizes must be special ordered. I got mine half price at an end of season sale. Liner underlayment depends on the soil. I have clay with no intrusions except a couple of smooth tree roots so I skipped the underlayment after the carpet scrap I tried rotted and stank to heaven because of the slow drainage rate of heavy clay even on a rise. Rocky soil or sandy debris would be a different story. Filtration and aeration is crucial. You can go with high-tech solutions or DIY such as the Skippy filter with poly quilt batting. I have a 100 gallon Skippy that I am quite content with. I clean it once in the spring and once in the fall. Others here will insist that high-tech is better. I do know it is much more expensive. You can always change to high-tech when more money is available. I think it is a personal choice. An over sized pump is better than one that is just barely adequate for the gallons. There are many factors that reduce efficiency. More gallons per hour going through the filter are better than less. I wouldn't use less than 2100 gph for my 1000 gallon pond and sometimes use a supplemental pump for various reasons. Expect someone else to add to this info. I don't buy or sell a lot of pumps so I have no way to compare. A backup pump can be a good idea for emergencies. I use a large aquarium bubbler in addition to the waterfall for aeration. Enclosed in a waterproof container it lasts about 3 to 4 years which is how long the diaphragm rubber holds out. That is what I would expect from indoor usage. I used to be able to find new diaphragms at pet supply shops but I guess no one carries them anymore. Aerators made exclusively for ponds are available. Electricity is essential and safe installation with a GFCI circuit is very, very important for safety. An extension cord is not a good idea. Sorry, I gotta go feed the critters and fix dinner. Hope this is helpful.

Don't get me wrong, I'm not saying that it is a huge danger. I'm just saying that the 'right' way to do it is using Wiremold to protect the wire (it's not the connection, it's the length of exposed wire that is the problem). In fact, if I was in this situation, I might even use an extension cord. But if I thought that the cord was in a position where tacking it to the baseboard would make it safer than just laying it on the floor, then I think it would be 'in the way' enough that I'd use Wiremold. If you're going to use an extension cord, I would suggest using one of the heavier duty, thicker cords that give it more protection. Those light-weight cords that are similar to the lamp's cord can get nicked pretty easily. And by the way, the fact that it is just a light load on the extension cord doesn't matter (although overloading an extension cord is a whole other problem that isn't a factor here). If a pair of scissors gets knocked off the back of the bed and falls on the cord and cuts through it then the resulting short circuit will happen whether there is 40W light bulb or a toaster plugged into it. I just believe people should be aware of the problem and then make up their own mind about what safety measures to take.

It does boggle the mind. I rented a place with a cord under the carpet that then ran to another outlet...up through the masonry and everything so it was a sort of 'professional' job, and let me tell you, until I spotted that cord (and even after) it had a pretty hard life. People walked on it, furniture crushed it, you name it. It was far from protected, but certainly 'insulated' if it overheated, but not insulated in a way you'd want! A guy I worked for had a door buzzer on the office door, and it was powered by speaker wire running between the carpet and the wall, jammed in there. That in itself might have been ok, even the electrical tape splices might have been ok, but in spots he thought it'd be really *neat* to run the wire along the nail/spike strip, you know, the wooden strips with the nasty spikes that hold carpet down at the edge? Naturally, spikes had penetrated the wire in places (240v) so some of those spikes were, I guess live. I was appalled. Later on, I discovered the wiring in many of the desks (desks had wired in outlets and light boxes that ran to plugs and outlets) had single insulated wiring or even exposed push-on terminals and exposed terminals on some of the fluoro ballasts, I discovered by accident reaching under and feeling these terminals... I persuaded the boss it would be in his and Workcover's best interest to get a sparky in to fix things. SParky was appalled, boss just left it to me to show him the danger spots since he didn't seem to understand at all how dangerous the situation was. Sparky suggested an RCD (GFCI) one of the ones that protects all the circuits, I was adamant we should have one, and, ironically, it saved the life (probably) of that same boss who, in his wisdom later 'demoted me' - ended up tripping the GFCI twice, once (I kid you not) putting a knife in a live toaster, the second time, adjusting a thermostat in an electrically heated splicer, that was still turned on. Guy almost Darwin Awarded himself twice later on with motorcycles, the second time he pretty much julienned himself hitting one of those steel cable guard rails....was lucky to survive, was triple lucky to retain his limbs. Here is a link that might be useful: Darwin Awards

It won't even necessarily work with DC. In fact, the reason it won't work is pretty much the same as with DC. First, note that half the 120V circuits in your house are 120V on one side of ground and the other are 120V on the other side of ground. Obviously the only two ways of combining this would be either a disaster (like shorting two batteries together) or it would yield a single, same amperage, 240V circuit. The other reason is that these aren't two fixed voltage, 20A sources. They're a much larger source that has a over current device that will shut them down at 20A. Now given the fact your house wiring past the breaker and your extension cords are unlikely to have exactly the same resistance means, that you'll likely flow 20A on one side tripping the breaker before you get 20A on the other side. Of course, once one breaker trips, the other will in short order as the whole load switches to that side. As pointed out the only sane solution is divide your loads. Note however what is going to hurt you running a wood shop in the garage on extension cords (been there, done that), is not so much the lack of current capacity on the individual branch circuits (within reason), but the fact your extension cord is most likely rather small and hence (you'll understand this from DC) higher in resistance which means that your delivered voltage will be significantly less than 120V. However, you can buy 12G extension cords (oddly they call these 30A cords) or make your own by buying some suitably large cordage and adding your own connectors. Of course, the only real long term happiness is to install a larger feeder and put a small sub panel in the garage to feed the various equipment. Some day you'll get a 3HP something or other and need either 30A 120 or 20A 240.