Thanks guys.....

I made a bubble counter.....not working very well.....it fills with water, siphons from the tank when I turn the pump on. Is it suppose to be placed above the water level or am I doing someting wrong?

I find the instructions for the disfuser (Aqua Medic500) to be very poor.

the pump is suppose to attach to the "outlet adapter" however this adapter has two places where the pump can be attached....I don't know if it matters or not which one.