Unless your leak is HUGE, you have to have the tip of the dye emitter (can be a bottle of phenol red) within 1/4" or less of the suspected leak location. I'm posting two short movies of me leak-testing a commercial kiddie pool. They illustrate (a) how to do it and (b) a NEGATIVE (no leak) result. I have to do some minimal editing on the POSITIVE test result before I can post it. I'll put the links in the following post, once YouTube has them live.