Sorry I haven't gotten back sooner. I've been traveling for work. There is no issue with mineral deposits in the geo unit using as open loop. The entire system is pressurized just like your well pressure tanks. Mineral doesn't deposit in your well pressure tanks, the geo unit is no different. Minerals can only deposit when there is no pressure and the presents of air or oxygen. The valve that allows the water to flow through the geo unit is on the water output side of the plumbing. That way the heat exchanger and coils are always under pressure originating at pressurized well tanks. I use my homes normal well tanks for the house water as the geo water source. I tap is off the tanks before the water softener. As far as the well goes, I had to go deeper to get the quantity of water I needed for the geo units, and I has to add a couple of extra pressure tanks to make sure the well pump doesn't cycle too often. As an extra bonus, check out your local power company. Most of them have preferred electrical rates for geo customers, usually less than half what you normally pay. You will have to have a separate meter and electrical panel, but that cost is minor to the huge savings you get by using electricity to power the geo units. Because the well is now needed to run the geo units, the well pump can be tied into the separate geo electrical panel too, so whenever you use the well pump, even if it�s for the normal house water, you pay the reduced electrical rates. As an example, in Michigan the normal electrical rates are around $0.11 per Kilowatt hour, my geo rates vary by time of day anywhere from $0.07 / KWH to as low as $0.029 / KWH. As you can see, the savings is huge.
I also use the geo units to preheat my hot water for the house. I preheat up to 90F, and yes, your electrical usage is all at that reduced rate!
