[Canadian]

I know the typical mantra is that BB allows you to push more flow through your tank and that's certainly true - you can without the risk of sand blowing around.

With that said, I've recently reduced the flow in my BB 24 x 24 tank and noticed a significant improvement in growth rate. Previously I was running around 75X my tank volume in flow and now I'm down to around 55X. I may be in a unique situation given how small my tank is and the fact that most of my corals are mini colonies and not large colonies yet. The smaller corals probably aren't impeding flow as much as would occur in other tanks or with larger colonies. But just because you can get away with running more flow in a BB tank doesn't mean it's the best decision.

I have a few theories on why reducing the flow has helped my tank. The primary one being that the lack of sand and my open rockwork minimizes the scrubbing of flow velocity that occurs in tanks with sand where the sand scrubs some of the velocity of the flow. Of course it may also have something to do with slower flow allowing the coral polyps more time to capture some food.