I am going to be turning my sons 15 gallon FW tank into a SW tank. It currently has a couple rocks, an under gravel filter and a HOB filter. The goal is to make this a quarantine tank for my main 75g reef but since it's also his room tank I wanted it to be somewhat interesting for him also. I am probably going to put a couple of reef rocks and keep pretty much everything in place but was wondering if I should keep the Under Grave filter? If anything just for aeration? We will toss the gravel out and go bare bottom and maybe get him a few cheap saltwater fish and some stairs.

