You have a lot of questions but you gave much more info than most newbies it makes up for it. LOL! I can't answer all your questions but there will be others along to correct that. No one pond is exactly like another and no ponder is just like another. I can't quite visualize your pond but maybe it will come clearer later on. You don't say why the pumps fail. If it is the same reason each time then I would think you should go to another type altogether. Or provide what it is lacking. If debris is damaging the pump then you need a prefilter which prevents damage to the impeller. Most pumps have a small and totally inadequate sponge in front of the impeller. Most of us toss it and install some sort of prefilter in it's place. Looking at your pump, I don't see even that, just a cap with lots of slots for water flow. Options could be change pump type, or remove filter cap and attach prefilter with sponge or other filter material. Algae is endemic when the pond gets lots of sun. You could use lots of chemicals but that is rarely satisfactory. A UV filter could work just fine by using a diverter or adding a small pump and filter. With your waterfall pump I suspect a separate pump would be easiest. More later, Sandy

Now, I'm getting the picture, although there are still a few blurry parts: When you say, "I'm more concerned about the chemicals in the untreated water." What do you mean by "untreated"? Untreated by NYC? You shouldn't be getting any of that. Untreated by you: we are not there yet, as your system is not designed. I suspect the "backwashable" system you found was a multi-stage system. The first stage is almost always a roughing filter, that takes out the big chunks, like rust particles and your up-state critters. Usually this is a 20-30 micron polypropylene filter, but to be backwashable it cannot be a "depth" filter, but rather a surface filter--the particulate must be trapped on the surface of the filter media, otherwise how would it be backwashed off? This type (surface screen at about 30 micron) may be all you need to segregate the carcasses from what you want to drink. The next stage usually removes dissolved iron--I doubt you need this, but you could install a 20 micron depth filter to get out all the rust particles and dirt and stuff that gets loose in old municiple water systems, and the final stage is the carbon filter that removes chlorine and other similar chemicals, which is usually unnessary--more on this later. You could taylor the stages to suit your needs. To one of your original questions, how much water flow can you get through a 1 1/4" service line? Probably 40 gpm. Using Hazen-Williams (google that!), the pressure drop would be about 50 feet of loss (that's about 22 psig, which is a good bit) per 100 feet of line and the velocity in the pipe would be about 10 ft/second--don't want to go much above that. But a better way to size the filter is to find out what simultaneous demand could you reasonable expect? Just add up all the users that could be using water at the same time, and size the filter for that. For the critters you describe, a 20-25 micron whole house filter should be all you need. I don't recommend the big blue filter housings, because I have seen them develop leaks and actually split apart at the joint where the two halves are fused together. The clear polycarbonate single molded housings or the full stainless steel housing with brass head are better choices. You can get either at w.w.grainger. The advantage of the clear plastic is you can watch the carcasses collect on the spiral-wound polypropylene filter media. ;-) What the Lurker was warning you about is that if you remove chlorine with a carbon filter, than anyone with "soiled" hands who touches the nozzle end of a faucet could transmit bad critters to that faucet, and you will never know and the critters will multiply and that spigot will be come the fountain of yuck. I have a friend who contaminated his whole well through such a transfer of bacteria. Bad day. Hope this helps. P.

POU (point of use) water filters are available in two versions... UNDER SINK... installs under the sink and has a dedicated faucet installed up top. Requires drilling if there is not an unused hole in the sink and only provides filtered cold water. COUNTER TOP... sits on the counter top and has it's own dedicated faucet providing filtered cold water. As long as you choose an industry standard (not proprietary brand name) filter there are a myriad of filter elements available to filter lots of stuff... sediment, chlorine, etc. There are even filter elements to add minerals back into filtered water. Is there something about the taste of your water you find objectionable? If yes then we need to identify the cause. If no and you just think that a filter is a good idea then what should we filter? I'd want to know what the water conditions are of the water at my house. A municipal water quality report is a start but does not always indicated the conditions of the water at your house but rather at the treatment plant miles and miles away. If you are really concerned then a test by a certified independent lab is the first step. Based on the test results we will know if a softener or RO unit or filter or other treatment is indicated?

Well, I'll do my usual thing and recommend a DIY skippy filter if you have enough space. Still very pleased with mine, it's into its second year of operation now. I have clear water, and so far NO maintenance or cleaning has been required whatsoever. For me this is a BIG consideration. No dreary filter cleaning... I just enjoy the pond, watching the fish and the teeming life in there. I don't use UV, so no extra on the electricty bills, and no new UV bulbs every year. Skippy's do need to be big compared to commercial filters, but mine is half buried, and forms part of my waterfall return, and is almost entirely hidden by plants and rockery around it, and watercress growing in the top. And it works WAY better than the commercial filter and UV that I had before. Note that although my water is clear, I have a LOT of mature plants in the pond and waterfall return, and about 60% surface coverage from lily pads, frogbit, water hyacinth, water lettuce, duckweed and azolla. This undoubtedly helps. Also, in my design the skippy filter is sitting in a lined "well", a few inches bigger than the skippy itself all around. So filtered water overflows into the well, and then overflows from the well into my waterfall return. ie. the well allows some additional settlement time for anything that gets through the skippy. By the way, the watercress and veggie filter stage (plants in the waterfall return) seem to be working extremely well, because the duckweed and azolla is not as rampant as previous years. Only need to scoop some out once or twice a month.