I was thinking since you said pump as late in the fall and as early in the spring as possible that our extra long winters would be to much time between getting flow through. Maybe cutting my carrying capacity is a better way to go.
This ground water is basically a weeping tile in my big lake with sand over the tile to filter it a bit. This water should not be very high in nitrogen( but I have no idea) I thought the Venturi would suck air and add oxygen to the water but again I didnt know there would be consequences.
Thanks for your inputs this isn't completed yet so it's good to know this stuff now.
