Is there a such a thing as too much flow?

oscarslr

New member
Wondering... have a 225 with 4 mp40's on 100% reef crest mode plus two K4's. Will too much flow affect PE and growth negatively? Haven't seen any bad signs but wondering is lower flow is more ideal?
 
as long as they are not being blasted you are ok, if you see the skin peeling off, you may be providing too much flow to that coral. it's all about how you position them.
 
I think that the growth may seem slower too because the branches need to be thicker and more robust to survive the higher flow, whereas in lower flow the branches can be thinner so they seem to grow faster. Best,
 
it is impossible for us to even match the amount of flow in the wild in our home aquariums, flow on the reef crest (the top front of the reef that meets the waves) can reach up to 3 feet per second, if i am not mistaken. that being said, a lot of corals sold are captive bred or multiple frags away from the original colony so some corals may have acclimated to lower flow than what is in the wild.

but yes, on an SPS only tank you can more than likely "never have too much flow" and like nemosworld said, as long as the powerhead is not blasting directly on the coral you should be fine. powerheads should be pointed into open water not at rocks or corals and as turbulent and random as possible.

mr. wiggles is also correct, higher flow usually means thicker and tighter branching.
 
There is no such thing as to much flow...lol just don't blast them..in my 5 foot 120 gals tank I run 2 mp 40's one at full blast, the other one at reef crest, plus 2 koralias 4...
 
I have 54 gallon corner shaped tank and in the front corners i have a K2 on one side and a K3 on the other. The K3 fires kinda straight at my neon green acro and its not really blasting the skin off but the branches go really odd on the side. The place where the flow hits on some of the branches they actually start to flatten and the coralites disapper. Other that those couple spots it grows like crazy and is always fuzzy with green polyps.
 
yea, blasting = bad, lots of flow = good

I jsut discovered yesterday one of frags (some sort of acro) which has a light yellow/green skin and deep green polyps in the shape of a V showed some tissue damage on the side facing on of my mp40w's, it seemed to be getting blasted, so I moved it, we'll see if it recovers.
 
Mine doesnt really seem to mind that much. Just on that one spot other than that its blowing up. Plus it keeps it away from the condy. I may swap it for a K2 one day but who knows. Lease it kinda works as a way to control its growth.
 
I run two MP40's on my 4' tank on full blast with four K4's and 1,100 gph return.

It takes a lot of tinkering to keep direct flow off of corals but none of mine are being blasted. A ton of random flow though. I estmate about 12,000 gph in my 120
 
Any thoughts on PE, I have some descent PE but I seen some crazy PE on tanks with less flow

not all acropora or so called "SPS" corals need the exact same amount of flow.

I have a hyacinthus that literally wants to be blasted. the more flow, the more PE i get. it is an encrusting/tabling acro so it likes laminar flow.

my Lime in the Sky was recommended for moderate to weak flow. it is an SPS and a stag/branching type so you'd think it would like high flow but in high flow its PE is very low...
 
Well..this is debatable. I've snorkeled and surfed my share of Pacific reefs and from what I see, we really don't mimic the intensity and the type of flow that corals experience. When a wave rushes over most reefs, the reef is usually more than 20 feet below the surface of the water. When you're down that deep, it's not the wave that you feel, but the surge-like vacuum that pulls you after the wave's swell passes. Between swells, the current pulls you in whatever direction the tides are moving at that given time. So, there are always at least two directions that reefs experience water movement. One is through the wave swells that pass overhead, and the other depends on the tides as they pull perpendicular to or toward the beach.

To say that flow is the same in our tanks is somewhat misleading. We generate flow from a point source like a powerhead, return or closed loop pump. It's much more direct than what is experienced in nature. I once thought about designing a perforated tank system by which water was moved by opening a hidden lift gate mechanically. This pull of water to a reservoir creates the displacement "rush" rather than direct flow and would be more in tune to what SPS corals experience in a high surge reef environment. Vortech pumps are probably the closest we have, but we're not there yet. If you don't directly point the Vortech at your corals when it's powering up, then there is probably no limit as to how many you could install in your tank. You simply won't be able to replicate (or afford to operate) a system that could move not just the amount of propulsion through a propeller, but the actual amount of that powerhead's power in displaced water moving in unison through the system like it is being pulled away. The feeling is much like the one you get when you stand ankle deep in water at the beach. As the wave recedes, you feel the pull of the tide against your feet. If it's strong enough, your body can even be pulled over. I can't even imagine that any of us has that amount of power surging through our see-through boxes.

With four Vortech MP40's in my 72 x 18 x 27 150 gallon tank, I can tell you that at first glance it looks violent. Any new fish that has been introduced needs time to adjust to the flow. In time, they all get accustomed to the surges and everybody looks more normal. I will admit that with these added flow rates, fish seem to expend more energy swimming into and against the currents in such a small space. I feed a little more than an average SPS keeper just to keep my fish from looking emaciated from the workout they get all day.

So, to make a short story long....crank it up and let 'er rip! Just don't point a powerhead directly at any coral.
 
There is some bad advice on this thread. :thumbdown

Of course you can have too much flow!

If you stick any SPS in front of the outlet of a Stream 6300 on full chat, it will not be long before the flesh is removed off the sps.

Constant rapid, over-powering flow will be bad for any SPS. In the wild during a storm, corals can survive, but it is far from ideal conditions and storms don't last long. The majority of time, the sea where acropora reside is not at white water rafting speeds.

It is very hard to replicate natural water movement within our aquaria. Short bursts of an alternating flow patern and or flow strength, like that which stream type pumps produce will be better, but its still not close to the entire body of water being moved, like the ocean.

The Tunze wavebox replicates this to some extent, but in the wild most sps like the entire body of water to be moving in one direction and not back and fourth (ala tunze wavebox style) at least, that is what I have seen when I have dived and snorkled in places like the Red Sea and the Indian Ocean. Spending time in the sea at the natural environments, looking at how waters move and coral positions can tell us a lot about what type of habitat these animals thrive in.

I have seen acropora and a host of other SPS ranging from near still lagoon water, through to reef crests where there is a constant laminar bulk of water being moved. This kind of tells us that SPS corals can and do adapt to exploit various locations within the sea.

Getting back to the question in hand, yes we can give corals too much flow. As a guide if polyps are finding it hard to come out and are flatened by the flow, this would be the maximum for a short duration (for pumps with alternating flow strengths). If you can not provide control over flow strength then I would advise you avoid creating so much flow, instead aim for polyps to be gently moving in the current, with the general aim to avoid any dead spots within the tank.

Remember too much flow will be bad for your corals.

Regards,

Tony
 
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