gasses dissolve almost immediately... the content in the water will reach equilibrium with the sorrounding air (in this case a many bubbles + surface contact with air) very quicly. if you ever go with a sepaate reservoi style, go with agitation > bubbles.. it's far more effective for larger volumes... ask any aquarium owner.
i would wager you don't need more for oxygen-related concerns, but if it helps agitate and otherwise avoid a stagnating bucket of water with some filler, then go for it.... if it circulates / shifts around enough as-is then it won't help much.