Percolator in bong bubbles/foams up oddly. Help.

I've had this bong since early '11, this problem never happened once throughout the whole year. I've since changed houses, and moved in with a new crew of mates. In the '11 house, it was just me smoking, and when my mates came over they would smoke up too. But now I m living with my mates that also smoke, so the bong is getting a lot more frequent use.

But basically, it's a 2 chamber bong, the beaker, and the percolator chamber. Whenever the water in the percolator chamber is left to sit for a hour or so or when it's not being used or whatever, it has a huge chance to like bubble right up to the mouthpiece when used next. It is as if, the bubbles like stack up all the way to the top and cling onto the side, it also brings up the resin stains all the way up. It's friggin bizzarre, and ruins many bong hits, by getting dirty bong water in your mouth during the pull. Whenever the water is cleaned out, the problem is fixed until it's left to sit again lol.

I clean the water frequently anyway, so it's not really a huge problem, but i just wanna know why the hell it's happening, i used to leave the bong to sit for ages with the same water in '11 and never once. But now it's a daily thing.

My theories that i have thus far, is that now I' m smoking with more people, someone is a drool-er or something, and when that is left it causes more foam like bubbling, i hope not though lol. But really i have no fucking clue, so any suggestions as to why this is happening, and how to fix it or anything would be greatly appreciated.

Black Leaf - 3-arm Perc Ice Bong with Ashcatcher - Blue - Percolator Bongs - Glass Bongs - Bongs and Waterpipes - Smoking Pipes - Grasscity.com

It's very simliar to this bong, except no colouration, beaker base, and no ash catcher. But the same perc, and that is where the problem occurs.

 

Bumps

 

Thanks for the suggestions guys.