Too much flow for acropora

[watdachuck]

FWIW I agree it is hard for there to me "too much flow" outside of linear direct flow at particular corals. However, IMO there is optimum flow where the corals are comfortable extending polyps, and debris is easily flushed away.

I have two MP60's on my 160G (24 X 24 X 66) on the same side of the tank but in anti-sync reef crest mode. They are set to 60% maximum which I estimate is a little less than 50X turnover. I did not run a controlled experiment but did find ALK consumption to increase along with PE compared to when speeds were increased.

 

[jda]

When tissue peels off of skeletons, then you have too much flow. When branches get so thick that they grow together, then you have too much flow. When acros are stubby, short and look like fire plugs instead of trees, then you have too much flow. When the fish are too skinny from swimming all the time and have scars from being blown into the corals, then you have too much flow. Most people never get here, but you can have too much flow.

 

[Rakie]

When tissue peels off of skeletons, then you have too much flow. When branches get so thick that they grow together, then you have too much flow. When acros are stubby, short and look like fire plugs instead of trees, then you have too much flow. When the fish are too skinny from swimming all the time and have scars from being blown into the corals, then you have too much flow. Most people never get here, but you can have too much flow.

Pretty much this.

It's also worth noting that in the wild, corals will eventually grow to the size where they are so dense they cannot get enough flow.. (Some species like Staghorns will never get this problem due to growth structure). But even in nature, a colony will grow until it's so dense and large, that even the ocean can't supply the flow demands. It then starts dying out from the center, and as the coral becomes more brittle with dead skeleton versus the growing outer rim, it will break and large chunks of the coral will fall and basically self-frag.

As JDA said (paraphrasing in my own words here) -- The only way to cause trouble via excess flow is by either being Irresponsible with flow placement / direct flow, or spending astronomical amounts of money on pumps. Both of which you have to go REALLY out of your way to do..

Another thing worth noting... As we see from the wild example I had written above -- As corals grow they need MORE flow. That means whatever you have NOW, will not be enough in a few years as corals grow larger and more dense. Most people don't realize this, and they slow down their tanks growth and health. But lack of flow is not only a real problem -- It's deadly to SPS. I often tell people to invest in one additional quality pump every 1-2 years depending on growth (If it's an SPS heavy tank). And maybe one every 3-4 years if it's LPS/Softy tanks.

So in a fe years, consider buying an additional pump

 

[jda]

I also believe that once you have "enough" flow, then getting "more" does not do anything.

On my 240, I have a tunze wavebox and a pair of 6100s... and about a 800gph return, if that. There is only acropora and clams in this tank (and lots and lots and lots and lots of coralline). Most people would not think that this is enough flow, but I get excellent growth, good formation and no dead spots. I know that I have enough. Now, the wavebox works wonders that most people have never seen with a 2" in-and-out swish every few seconds to every spot of the tank. Even though the wavebox is capable of keeping stuff stirred up and can get into every little nook & cranny of even the most dense corals, you still need some flow pumps to move water around. I will always have a wavebox if I can - not all tanks can do it, but if they can, I am going to have one.

 

[SeeFu]

I keep my power heads up high and pointed at eachother from across the tank so the streams collide and they are on Else mode which is random ramps up and down.

We were in between colors when I shot this vid so dont judge but this is how most of my acros are and they seem to be happy.





I also agree that basically every coral loves at least moderate to heavy indirect flow.

wow that's a lot of polyp movement. i have a 5" wide 125 gal w/ 2 gyre's running at pulse 90% and i don't get anywhere near that type of polyp movement.

 

[tjcmtnbiker]

I notice that after I spot feed with pumps turned off, the long sweeping tentacles come out. After about 10min, I turn pumps back on and sometimes the tentacles get pulled off. Im assuming that is too much flow?