Hi cody94549, Use your city tap water (or well if applicable) and an in-line water filter (yes, you really should use a filter). You may find the following helpful:
JoeD's TGTip 0001
MINIMUM WATER FILTRATION
Always filter your TG water... regardless of the source.
(read that again)
At a minimum, the water filter you use should have sediment + carbon + KDF filter elements. The filter I usually recommend that meets those requirements is:
Camco 40043 TastePURE Water Filter w/ Flexible Hose
Replacement Cartridges: Camco Water Filter, 2 Pack
* READ AND FOLLOW ALL FILTER INSTRUCTIONS.
* The slower water passes through the filter, the better the filter works.
* Always start a new growing season with a fresh filter cartridge.