I have a 75 gallon tank with 2 bottom feeders and 8 african cichlids, I am going to be going on vacation for 2 weeks, does anyone know if I will be ok with out changing my water for that amount of time? also, which sould I use, Feeder gel, feeder Tabs, or automatic feeder; or are all of these just personal preference? Also how long can they go without eating??