[glampka]

Marcie,
The flow is coming out the bottom?? It sounds like they are running in reverse. The water should be flowing out the smaller opening. Most ph have a tapered "screened" intake that fit into the uplift tubes of undergravel filters. You can take a short piece of 1" tubing, drill a few holes in it & use that as a guard or you can get sponge filters designed to act as guards. You will have to clean the sponges every few days as they will act as a filter as well.
What powerheads do you have?