Thanks, I'm going to use the y fitting idea. As for intake I'm going to go passive. The only reason I wanted to use an intake fan was because I was concerned with getting fresh air to the bottom and back of my space. Using Dryer Ducting I can cut intake vents in the same wall as my exhaust and just run the ducts to the back. I can aim fresh air that way as well.

I'm still thinking about building a floor with space underneath for venting. It may help keep my reservoir cool if I vent cool air under it. I'm still leaning towards dryer ducting for the simplicity of it.