you might ... brass is pretty hardy stuff. I'd be worried about pumping nute solution through it. I find plastic Ts with no problem at Home Deport in the "irrigation" section. I think that's a safer bet.
well i sealed the other side with sylycone because i lost the stopper and just ran the hose through one side but i might get a plastic one like you said.
If you're using it for air lines, you'll most likely be fine. DO NOT EVER USE ANYTHING BRASS FOR WATER, EVER. Brass fittings will corrode faster than ever especially if it's exposed to nute solutions. Corrosion will dilute and even in the smallest PPM's will fuck your plants hard.