When you say ‘fittings’ what do you mean? Are you going to use S&D pipe? You mentioned ‘hose’ just trying to put it all together. 

I’d recommend 4” metal blast gates. They’re not too expensive on Amazon even and ca be cleaned and retrofitted with other goodies in the future if you wish. 

Ryan/// ~sigh~ I blew up another bowl. Moke told me "I made the inside bigger than the outside".