[Reefland]

As some of you may know, we are running a pretty agressive amount of flow in our 75 gallon SPS reef tank with 4 MJ 1200's and 2 Tunze Stream 6060's running. The only purpose of adding this much flow was to keep the tank clean with as little manual work required as possible.

The concern I have is that we are comprimising (or trading) outward growth (length of branches and additional branches) with thinker branches due to the amount of flow. Growth is based on the rate of calcification and if the coral is adding more density to the branch to comensate for the flow, the branch length or additional branch growth is traded.

We are seeing growth on our corals, and lots of encrusting growth but I think we are seeing more densifying than growth development.

Any Comments?

[Samper]

I don't by any means know anything about this but it seems to me that a thicker coral be slightly healthier and possibly more resistant to predators, breaking etc? I get the picture of a very skinny frail person standing next to a football player.

Which species are you talking about and in the wild are there variations on how they grow in different regions under slightly different angles from the sun?

[zhenya]

Originally Posted by Samper

I get the picture of a very skinny frail person standing next to a football player.

Hey, stop talking about me,Samper... j/k.

Scott, I think what you are seen is pretty normal,i.e heavy encrusting and branch thickening.I'm sure when all those frags start to grow out into a colonies they'll be just fine and will grow evenly.
On a side note, I don't have even a half of the water flow you have so it's hard for me to see difference in growth rates.However, I would assume that the coral would accelerate calcification rate to compensate, providing that it has plenty of energy to do it...I think.

[stang69]

If I am not mistaken they are building a stronger base and thicker branches therefore it will take longer to grow thicker branches than longer ones. Like I said I dont know but makes sence to me



Jeff

[Samper]

That makes sense to me too, they would need a much thicker base in order to support the outward growth in a very strong current. You might end up with some of the thickest most healthy specimens yet.

[SueT]

Yet I'm seeing something different. Since I have a tank 15 weeks post set up and it is full of frags of mostly acropora species and some plating montipora, what I am seeing is a lot of encrusting base growth but on some I am seeing little to no base encrustation while lots of new branches. No particular place in this 120g has more flow than another. I'm running about 15x turnover right now.

All are obviously growing, some extremely fast while some are doing this no base and upwards shooting branches thing. The species doesn't seem to matter either.

[Poseidon]

Boy Scott... here's my .02, I think a "coral" can only grow as fast as it can absorb Ca and Alk. That growth is either going to be used for girth or length, or some cobination of the 2. I would say the rate of your Corals growth matches mine and Zhenya's and Ninong's and everyone else's that has the "right" conditions. That being said, your corals may just be growing differently, not more not less. I'd say give it some time, and once you can frag something into 2 identical sized pieces, photograph both of them. Then give one to someone who has less flow then you, (like me ) or Zhenya, Ninong, etc... Then after 3, 6, 9 months have the frags photographed again, with a ruler behind them. I think this way you can compare the growth at least in theory... Of course the lighting and food and such also will have an impact so maybe thats a waste of time!!! ARGH!! I dunno! It's an idea anyway~!

[Reefland]

Obviously the increased flow provides a better opportunity for usable food to reach the coral. The increased amount of energy would provide the coral the opportunity to increase growth rates but even then, wouldn't the increased rate of growth be utilized for the needed thicker branches to handle the water flow?

My tank is turning over more than 4000gph; more than 50x the water volume of the system. This still isn't comparable to nature but when we're dealing with tank raised frags which are used to less, it makes me wonder if a reduction in flow would yield more outward growth.

[zhenya]

Scott,

I don't think you should have any problems with growth rates, lateral and vertical I mean. Once the frags encrust enough to support the growth on the periferal, it will begin growing outwards. How fast?That remains to be seen
I hope you taking pictures regularly to compare,using ruler like Mike suggested is a great idea.

[LazyReef]

All corals have morphological variations depending on the different spots they grow. Depth, light, flow, food, sediment, predators, etc. I think its a great experiment. Good luck.

[qwiksilver]

Lazy reef is right... they all have morphological differences. Given different depths, lighting, flow, etc., every coral will grow to suit. Take some of the plate corals (Montipora) for example. At deeper depths with less intense flow they spread out horizontally, whereas at shallower depths with more intense flow they grow more vertically to create a stagnant area like a cup to trap there food. Zhenya was also right in saying they have to grow a stronger base before growing taller in order to withstand the current. Some corals, though, are notably found growing thinner in higher flow areas for the main purpose of asexual reproduction, whereas others grow thicker and more dense and take years but mainly propagate by means of sexual reproduction.
Also, the higher the flow the tighter the branches have to grow together to be able to trap the amount of food they need. It will create a slower flow moving between the brances thereby giving the polyps a chance to feed properly. But then, after they grow tightly together and you change the flow to slower, you might possibly find the base begin to die and the central shoots of the colony due to not ENOUGH food cause there isn't enough being carried into the central areas of the colonies. JMO

[Chris Lakies]

Scott,

I would think as long as the force from the water isn't tearing the flesh off the SPS and the pollips are able to extend fully......the more water flow the better. This allows for constant amount of nutrients, and washes away any waste products from the sps. I have about 40x turnover in my tank.

[LazyReef]

I would differ on the opinion of constant flow at high velocities. Some polyps extend more during slack and ebbing tides. If I were to think about optimum conditions of flow, I would have to a varied current, with slack times. I am far to lazy, however to go with a wave device. I use constant current and just enough. I definitly like flow bars in the back of a tank, but they eventualy clog with worm and coralline growth and crap, and I haven't moved my rock in eight years. I think when you are considering flow in a reef tank that there should be enough flow in the tank to keep plankton sized particles (or detritus) suspended, but not to much that a polyp could not grab it. Granted that 90% of SPS energy comes from symbious... If a sand sifter can put it in the water column I wanted enough flow to carry it over the overflow and into the filtration.

I think that the thickness of a coral branch would be far more dependant on the alkalinity/calcium values, as well as the ratio of Ca, Sr, and Mg. You can have all the flow in the world but you have to have the alk and Ca high. Making it easy for the reaction to go and form the Calcium carbonate structure of the skeleton would save the animal from exerting energy. I don't think flow would factor in as heavily into the growth equation over chemical factors.

The unsheltered sides of islands are usally where the SPSs are, but not all. Some species may be especially evolved to grow stronger so they can out compete a more frail species in stronger currents, while others are ususlly more fail since they mostly settle in lagoons or aft reefs. I have seen Pachasyras and branchy SPS grow out in lagoons in the Solomons. Small stubby acros in the shallows that almost get exposed at low tide growing in Tonga. Porites and monitopra dominate walls in the Coral Sea and leptoseris, favites and green flourescent corals a little deeper in Tonga. I have not dove everywhere, but I get the impression from my observations that the SPS corals like a little shelter and slack. For example I found a huge conoly of bubble coral growing in 50 feet of water in Tonga on the sheltered side of the island. The colonies were huge seperate torches five feet long with just the bubble on top. We only see the top four inches in the hobby.

Euphyllias were in similar locations as the bubble, so the wavy tentacle corals I think like calmer water. All the species of T. clams I have seen have been in lagoonal or protected areas. So if you have clams, I don't think they like strong current all the time.

I think I maybe conviced myself I should have a wave device after all...

[Samper]

In the new tank of the month on reef central this is what he says.

The constant switching of both the SCWD and the Sea-Swirl operating independently of one another provides very chaotic water movement, never allowing any stagnant areas in the tank for long. Many reefkeepers who have seen my system comment on its high amount of flow, and I've also noticed that many of my SPS corals grow thicker branches than normal as a result of the increased flow in comparison to other systems. While this may sound a bit complicated, the general theme is lots of flow provided in the most chaotic way possible

[Reefland]

SueT, I think your observation of random growth speed and pattern is interesting. One day I'll be able to do some experimenting with frags taken from the same colony but placed in different locations to see how flow and lighting affects the growth in the same system.

[Papa Doug]

This is a pic of a blue tipped acro frag. On the left one can see the largest part, which was the frag itself. {only about an inch high}.

I thought this may be applicable to this topic because of its growth so far. As can be seen, its encrusting way more than vertical growth. It has lots of new vertical tips growing but not very high yet.

This coral is sitting pretty high up, in the open and gets lots of random current from the pair of stream pumps. When it was being held in my friends 180 soft coral tank with less current, it grew just as much vertical as encrusting.

Now perhaps lighting also plays a role in this versus water flow. I dont know. His tank has 400 Radiums and mine 175w 10K Ushio,s.

[Reefland]

The literature I have browsed through recently supports your observation in regards to increased flow. The rate of calcification increases, but not necessary shown in lateral growth. That would leave thicker branches and more encrusting occuring around the base.

[Samper]

Makes perfect sense.