i am using a 85 gallon plastic lined hot water heater as a hot water storage tank for my DHW, the tank will have two heat sources, one will be the desuperheater on my 3-ton forced air geothermal unit, this will be plumbed in through the hot water outlet and the drain valve, the second source of heat will be my 2-ton water to water geopump, it will bge set up for 3 zones, 1 my basement floor, 2 my garage floor, and the third a flat plate heat exchanger with the other side heating my hot water tank, i'm not sure where the best place to tie it in, should i hook it parallell to my desuperheater connections or should i plumb it in to the electric element sockets, since the elements will never be used? as a note i will be using food grade antifreeze on the heating side of the heat exchanger. the reason i am using 2 sources is, the desuperheater will only make hot water in the heating and cooling season, spring and fall it wont keep up, i want the second source to keep the water at a decent temperature to minimize the amount my downstream electric tankless needs to run.