My Water Furnace brand of geo-thermal system has a loop in a pond ~250' below my home, with the pipes buried in a 3' deep trench to the pond. System was installed in 1998. While the system "works OK" , the pond loop pipes, a cloverleaf affair, have risen partially(as in slightly) above the surface. They were orginaly sunk in the pond & wires with concrete blocks were placed over them to hold them down. The original contractor is long gone. I called one HVAC guy & his answer was "do you want me to do it or you? No "so-called secrets were revealed" and I'm wanting to do it myself for certain. I may wait until it's above zero... I'm wondering: "how do I re-sink these pipes"? I've considered using sandbags(never found a source for the ones like the military uses,etc.) & could also use more concrete blocks with heavy romex tied on? I tried a google search & never saw a single solution! The comments are always lacking the detail of the actual means to sink the loop. I had the loop recharged a few years back & has performed OK since then. Ideas?