I,m a DIY with and usual situation. I'm going into a spring fed under ground stream that is about 9ft down about 40ft back of my house. Check and found one forum where someone had done this they said 450ft 3/4" per ton should be enough. I'm in Southern Indiana about 10 miles from Louisville, KY. I got 500ft easier to cut. The flow from Oct.15 till Jun. 15 is about a 4" pipe running constantly full. It tapers down in summer to about a 1/3th of that but never stops. My question should the line going to the loop be at the lower level with the rest of the loop, or should it be higher. Also should it be up stream or down stream. I have a good back hoe and a huge amount of construction experience. Already have set up dewater. John Miley E. A.