It's possible there's nothing wrong with the Acro that tuning won't fix. What exactly is causing it to buzz? If it's a tom (usually a rack tom) check the tuning of those two drums with the Acro snares off. If the two pitches are closer than a whole step, tune them further apart.
If it's the bass drum tune the Acro higher, as suggested, by raising the bottom head. Don't be afraid to crank it. You can use the top head to work the pitch back down some.
Good luck.