Hey everyone!

I've been looking around in different forums to see what the best practices for shrimp tank setup are and I can't really get a definitive answer. Currently I have a plain Jane, freshwater tank. I want to convert this tank into a shrimp habitat without too much fuss.

The tank is a 15 gallon, 13"x13"x20" (approx.) tall column tank. I've got a basic HOB filter, a small heater that hangs at the top of the tank, and a little bubble stone with an ugly air tube that I'm having trouble hiding. I have a gravel substrate, fake coral and skull decoration, as well as a tall fake plant. The lighting is kinda crappy, but it can be easily altered.

My questions are:
Do I need a different type of filter? or just a sponge to keep the fry from being sucked up in the filter?
Are the basic heaters good for shrimp?
Should I find a new way to introduce air into the tank or just set it up better so it looks nicer?
Should I buy a new substrate or is the plain black gravel ok?

I plan on removing the plastic decorations except for the skull and carpeting the tank with Java moss. The lighting will need to be changed so that the moss doesn't die. It can grow in lower light, but the tank is too tall for what I've got.