I pump river water to my irrigation system and it's all good. Going to use same system to put an open loop system into my GEOThermal setup. Two Questions; In contractors view, River water (I have a great filter) can still clog the system. He recommends another fine filter the help. Any idea's on one? I assume it can be cleaned regularly. Also, is there any preventative maintenance I can do (contractor can do). Say, once a month/year, clean out what might "clog"? What is the part that could clog here? Is it expensive to replace/repair/maintain (clean). Next Question. Assume I will be using the river water to help heat in the water (when air is below river water temp), I can "freeze" protect as best as possible any exposed pipe near the unit but the pump / pipe coming out of the river is going to be harder to protect. To date, I go for the low-risk option of winterizing the RIver pump but now I won't be doing that. Do I have to go back to a submersible pump or, is the risk low given the temp flow from the river, when it's really cold should result in the system coming on enough times in a cold night to prevent freezing. The river is rarely below 45 degrees!