Since a couple of people with a love of large fish and large tanks with large filters seem to be having some problems understanding what I wrote in plain english while singing around the campfire. Your filter--which you put up for comment is based on the same principles as many commercial and industrial filters. It is a self cleansing backwash filter that is all, and it filters down to 40 microns. I commented that this will clarify the water but will not remove disease organisms. If that is what you want and you can afford it then it will be ideal for you both and I hope you get one each for xmas.The purpose of my comments about treatment of rural water supplies was not to get you both joining in the choruses around the campfire but to point out that prefilters are often requred to avoid too frequent a need to clean the finer filters. Your xmas present overcomes that by automatically backwashing the filter to clear it. However it will not filter diseases and I wish those filters were still available. I think my comments were relevent and were in no way intended to denegrate either of you or large fish tanks with large filters and I hope you continue to contribute usefully to this forum as you have been doing.