I just painted my aluminum siding using barn and fence paint. it looks really good but i noticed when water gets on it water marks appear also tiny water bubbles form when wet and you can wipe the paint right off. the siding was clean before i painted it and was wondering if buying a better quality paint and going over the cheaper paint in the same color would help this? please any advice would helpthanks! Also i did not prime before painting ....Basically what i need to know is if i paint over the cheap paint with a high grade paint will it bond better then the cheap stuff already on there or is it gonna do the same as the cheap paint? also the paint i have on there now is flat latex. maybe i should go over it with satin latex? i noticed satin has a better durability then flat.