Look for deals on digital timers, Target and WM have them for less than $10, sometimes quite a bit less. I picked up a few that were discontinued models in WM for less than $5, once in a while RiteAid (of all places) has some for free or almost free after rebate.
10cc not enough for you? Wow. My 100gal is (under?)dosed with 4cc daily.
Congrats and have fun on your honeymoon!