I am in the process of setting up a 65 gallon freshwater tank. My well water is very hard ((23 grains, thus requiring a softener) and nitrates can range from 11 to 22ppm. I plan on diluting my well water with RO water purchased at local grocery store (fill your on container for 25 cents a gallon). During water changes I would like to pump the water from 5 gallon containers to the tank. Total vertical height is about 5 feet. I'm looking for an inexpensive small submersible pump that would make water changing much easier (1 gal/min flow rate or less). Does anyone have any recommendations?