Starter at 12 days is slowing down

Hey Folks:

Here's a digest of the first 10 days: http://www.thefreshloaf.com/node/62865/help-starter-10-days

Basically I had a starter that was doubling nicely every 10-12 hours from days 7-9. Then when I increased the feeding ratio from 1:1:1 to 1:2:2 the growth slowed severely. Seems like I've diluted the colony too much? When I've tried to push the temp up with a heating pad, it grows a bit faster, but smells quite alcoholic. Last night I returned to 1:1:1 feeding ratio and growth was at about 30% this morning.

Major factors that are different than most starters: I'm using 100% whole wheat flour (until my bread flour arrives), and it's a bit coarse (maybe hard to digest?), and my apartment is cooler than most (64-68 most times). The only other flours I have available right now are bleached AP and potato starch. Not sure if either of those are good for feeding or not.

Should I just keep on trucking? Anything I should particularly pay attention to? I plan to continue 2 feeds per day at 1:1:1 and hope for the best. It just seems strange that I built up a good strong starter, then it crashed when I gave it more food to eat.

Thanks for any tips!