For BioShock on the Xbox , a GameFAQs message board topic Just wondering how many extra slots you buy because I don't want to. ok, i've been able to buy extra slots for the plasmids, BUT how do i buy extra slots for the tonics? I have ADAM and i'm ready to buy, but. Tonic Slots allow the player to equip passive Gene Tonics. Tonic slot upgrades allow the player.