well your first problem is that youre putting you wee in the bowl...whatever god gave men a wee for, its not for sticking in bowls...

no but seriously, whats happening is probably its not very aritight(tape is NEVER airtight!) and the smoek is getting very thin to the point that you cant really see it in teh bottle or nothing.

id also reccomend ditching the bottles though, if you really wanna make a cheap home made bong, make a waterfall bong out of a sobe bottle(if you dont know what that is....google it)