It's good that you use bottled water, but distilled water is not healthy for fish. I buy several gallons of regular spring water for $0.55 a gallon locally.

Also, TM, 68 F is WAY too cold for a betta! They should be between 76 and 82 at all times! My beautiful boy stays at about 80 during the day and high 70's at night.

Here are some good links to check out:

http://www.healthybetta.com/Betta_Care_Sheet.pdf

http://www.bayoubetta.com/basic_care_sheet.htm

Hmm...It's been about a week since I did a water change, I think I'm going to go take care of that now! My poor boy, LoL! I ran out of live food a few days ago and he doesn't care for the pelleted stuff.