Could you please help me with pipe sizing and let me know if I am trying to replace 2 Spit System heat pumps, one (4 ton and one 3 ton) with Geothermal units, can I use 1 loop for both units or would it be better for each unit to have its own loop? These are my conditions: Large Lake 75 miles long) Lake is 300ft away from house downhill with 10ft of water under the floating dock - elevation from house to Lake is 15ft below house level - I was planning on a closed loop system with Coils built on a PVC skid with Blocks underneath for weight - Location Upstate SC - Lake never Freezes - I would like to only trench in 2 lines to the house to feed both units, but If I need separate loops for each unit that will be 4 lines up from lake I think?? maybe 1-1/4 feed lines??. I was planning on 2500ft of 3/4 HDPE for the Loops (1000ft for the 3 Ton and 1500ft for the 4 Ton unit with 1-1/4 or 1" HDPE To feed the Loops from House? I have a Socket Fusion welder and dies up to 1"-1/4 IPS pipe if needed. I would need to enter the slab foundation house on the 3 Ton Unit side of the home and go up wall to attic. (Home is on a slab). Then I could go through the Attic to get to the 4 Ton Unit which is about 50ft away. I plan to replace both Units with 2 Geothermal Units and plan to mount both Air handlers/ Compressors/ evaporators/ complete package units in the Attic, unless it makes more sense to do one Split geothermal unit outside to handle both units?? I was looking at using ¾” 500ft coils to reduce the size of my PVC platform but I cannot seem to find ¾” plastic spacers for the coils anywhere?? Are 500ft coils Okay? Thank you in advance for your thoughts, opinions and help.