I sussed it out earlier!, The fan would be drawing moist air through itself as well as sprites. not good for for the health!,
of the fan that is! 
. the house I live in has gas central heating, it dries the air out something cronic!. so the humidity caused by the bong would'nt be life threatening in my case
also you could always vent it out a window/whatever.
I think I'm gonna go bong rather than rad. I'm planing on putting a 220watt TEC in my maze3:1, and anything that'll cool water to below ambient temps gets my vote
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Thanx for help!
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