Yup. I have been running one for 4-5 months give or take. I put all of my sponges in the bottom tray. Each tray has a seperator (so you can layer the different grade sponges your referring too) Least that is how I run mechanical on mine.
To be honest though, a single XP3 will not mass filter anything over 75 gallons, and it will barely keep up with a 75, depending on your stock.
I run a Magnum 350 for mechanical along side my XP3 on my 75. You cannot beat the old school Magnums for mech filtration, those things will suck a golf ball thru a water hose. lol
If it's a new XP3 though, OP will want to run the same setup to get good bio going, thus having 2 chambers/baskets full of bio media, and the bottom for mechanical.