New Thoughts on "Adequate Flow"...

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I was thinking of how the current will be continually sweeping out old and new products, where our systems are closed.

 

[Amphiprion]

I actually asked this question a while back and puzzled myself a bit. I asked Eric for his insight on the matter and his response was as follows:

There is a big difference in the two. Very few corals need high velocity, though some do only feed at a certain velocity, although this is easily reached in tanks, even with wide-flow sources (i.e Tunze, Vor- tech). Given a choice, I would prefer bulk movement, and I think bulk movement is critical even in "low velocity flow" tanks. It's the nature of the ocean, but rarely tanks. Also, I wouldn't worry about "dead spots." They form their own small microhabitats with a difference species composition, increase diversity, and are probably more helpful than harmful unless the whole tank is a "dead spot."

The entirety of the thread can be seen here

 

[KarlBob]

Wow. Giving the dead spots some love. Never thought I'd see the day...

I dunno, but I suspect there is a threshold between tolerable dead spots vs. damaging dead spots. I have no idea where it is, but I think the amount of detritus in the tank plays a role in determining how much dead space is tolerable.

 

[Amphiprion]

Dead spots became another portion of the discussion, but mainly supposedly function as a favorable site for certain planktonic organisms. Seems logical, but most tanks likely have a few spots, even small ones, that serve that purpose. As long as there isn't significant settling, I don't worry about it.

In any case, I think the idea that we are starting to have very low velocities may still be a bit unfounded as of right now, depending upon the situation, of course. If you have something positioned a significant distance from a source of water flow, you may have some difficulty with some corals. But for most, I don't think it is much of an issue. I guess the real question would be which corals actually need the higher velocity, or rather, which growth form of which corals...