Actually not much flow. Coincidentally, I took the Marsh-McBirney electronic digital flow meter this afternoon. The highest velocity we saw was about 4 inches per second and often much less. Compare this to a 6" per second oscillating flow I saw on a Hawaiian coral reef on a calm day. But corals are growing quite well at the LFS - the Cyphastrea I got had encrusted the frag rack and had to be pried off.I bet they have great flow!