You need at least a 1000L pump or many pumps equivalent to 1000L.
30 gal is big though and I've never gone over 50L bubblers but in them I used 600-800L and it worked fine. As for airstones; never been a problem for me. Just the fact that the water is moving is making it aerated.
So it might depend on the dimensions of the container but try to spread out the stones.