I want to install a PVC discharge line from my filter to avoid having to deal with those plastic backwash lines. I want to run the line about 100 feet - but I'm not sure how much depth and slope I will need. I live in Georgia - so I shouldn't have to worry about water freezing in the lines during the winter. (Of course, the line will only contain water when using the Backwash or Waste cycles on the filter - and the water will be under pressure at that time, so there should only be a minimal amount of water in the lines at any time when it is not under pressure.) But, to avoid water flowing back toward the filter, I would assume some amount of slope would be required. Any recommendations would be greatly appreciated.