ima lil confused too..your tent is ontop of your bathroom?? and are you circurlating the air in and out threw the bathroom..
meaning..the hot air is going in the bathroom..and your trying to suck cool air out of the bathroom as well???
if so..that could be the answer right there..its hard to suck cool air out of the same room,warm air is getting blown into..id stick a fan in the bathroom if thats the case.