Sound OFF: It's all about that FLOW that FLOW that FLOW!

[Thales]

Me too but which is better ?

What does 'better' mean?

 

[SDK]

Lots of both types of flow on reefs, actually....

Reefs in areas with strong tides probably get more laminar flow. Reef crests that are part of atolls get more of the crashing/chaotic version. I've spent much time diving in both environments. Either getting dragged along by tidal flows or hopping into the "washing machine" of surf zones. I've seen the same corals in both environments, sometimes taking on different shapes.

I think as long as there is adequate light, flow and oxygen content, it makes little difference in our tanks or on the reefs which kind they are primarily getting. I also agree with those saying that it's difficult to truly recreate natural reef flow patterns in an aquarium. It's probably good for us that it is not terribly critical to have more of one or the other....

 

[Brew12]

Laminar flow is superior imo. As soon as laminar flow hits an object the flow will turn chaotic. Laminar flow will get more water volume moving a further distance than a "chaotic" source. When we point two powerheads at each other to create "chaotic" flow what we are doing is reducing the velocity of the water prior to reaching the coral. I would prefer to let the coral itself receive the full velocity and allow the chaotic characteristic to occur at the coral boundary layer.

 

[Brew12]

My couch is a bit like a holiday inn...

Your couch has bed bugs!!


Edit: No offense was meant toward Holiday Inn... was only attempting to offend @4FordFamily

 

[alanbetiger]

what is "better"
From various speakers (which I do not have information) laminar flow is what occurs most in nature so should be "better" for our reefs
However most aquarist like the look of chaotic flow. So it's better aesthetics but not necessarily "better" for reef aquariums

 

[mta_morrow]

I have both. 15-20 seconds of laminar flow followed by 5-10 seconds of turbulent flow.

I am running 2 gyres and have programmed them to give me that.

 

[Kmsutows]

I dont think it's so much a this or that question so much as chaotic laminar flow... if that makes sense. Back and forth laminar is what I wish I had and will do some day. I currently have a mix instead of what I describe as idea... like tides/waves in and out

 

[Js.Aqua.Project]

I think if you looked at a "zoomed out" profile of my aquariums it would look more laminar as you would see Gyres pushing sheets of water in what is attempting to be perfectly cyclical motion.

But if you look at the corals/rocks/crevices you will see more turbulent/chaotic flow patterns where the flow is hitting and bouncing off of the rocks and everything else in the tank.

I personally vote that - whole scale - laminar is better as it helps move food/debris through the aquarium to the appropriate destination more efficiently.

 

[Epic Aquaculture]

I use 2 Gyre 350's and 5 Neptune Wav's along with my Abyzz A100 return pump. This gives me lots of "turbulent laminar flow"

 

[vanpire]

I love diving, but I've never dove at any locations where I felt like I was inside a washing machine. I imagine that would be very dangerous as you would have a hard time controlling your movements and you are close to corals. I have been diving long enough to know I cannot fight water currents. I am not saying it doesn't exist, just I haven't been at those spots.

I have been to these:

1. Drift dives - water movement in one direction. Some are slow and some are high speed which are really cool. Obviously, these are laminar.
2. Surge-like - These dives are interesting as I can be remain perfectly still but the I would be moved 3 feet to the right one minute and the next minute the I would be moved three feet to the left. And it repeats.
3. Beach dives - This is probably the closest to a washing machine as there are many direction for water movement but still 90%+ of the water movement is primary in two directions. Usually toward the beach and then away from the beach. Usually I snorkel as I get closer to the beach.

From my own experience, I get the best growth when I use periodic laminar flow. Water movement in one direction for a few minutes and then reverse the flow direction in the next few minutes.

 

[Dr. Dendrostein]

What does 'better' mean?

That's a good one, Richard. Your killing me, man, just shot me get it over with.

 

[eatbreakfast]

I would describe what I have to be beneficial as organized laminar flow. I try to create a gyre type effect.

Think about kids playing in an above ground pool. If they decide to run in the same direction they can generate an immense amount of flow throughout the entire pool. Wheres if they all doing their own thing there will be some spots with alot of agitation and plenty of spots with no agitation.

To try and replicate that effect in aquaria is to have return pumps and powerheads positioned in such a way so that flow from one is directed to the next pump, in as much of a circular pattern as possible.

 

[fragit]

I can’t vote because I use both. I have a peninsula type reef. I have a Gyre on either end on anti sync to create a back and forth laminar flow, my return pipe is connected to a SeaSwirl to create some chaotic flow. My softies and LPS love it!

 

[sfin52]

Obligatory “it depends” post. I am not an expert in this subject matter so I just thought I’d contribute what is always the answer to nearly any A or B question

But did you sleep at a Holiday Inn last night?

He did the couch

 

[sfin52]

Our tanks are more like this.

 

[MrObscura]

Ive found that all my corals appreciate flow, as long as it's indirect and random. I'm pushing 100x turnover total capacity and even my Lps are happy as can be.

 

[SDK]

I love diving, but I've never dove at any locations where I felt like I was inside a washing machine. I imagine that would be very dangerous as you would have a hard time controlling your movements and you are close to corals. I have been diving long enough to know I cannot fight water currents. I am not saying it doesn't exist, just I haven't been at those spots.

Washing machine is an expression divers use to describe conditions where you are diving in area of random currents and surges that come from different directions. It does not mean that the water is actually as shallow or powerful as being thrown in a real washing machine...


Imagine the back and forth surf condions of a beach dive, but in an area of coral reefs. All of the random and varying structure of the reef deflects the water both on the way in, and out. It causes odd eddies, waves bouncing in unexpected directions, etc. It’s not more or less dangerous than any other diving as long as you adjust to the conditions and are expecting them when you get in the water...

 

[w2inc]

If you had to choose one...

If laminar is defined as heading one direction, I am really leaning toward that. When I move enough volume through my tank there is plenty of swirls and random flow to make polyps sway.

I have a 120 that has mp-40's on opposing ends set to blow random surge against each other. If I turn off the pumps blowing right to left on the back wall, the surge pattern seems create some really Mellow and almost dead, flow areas in the middle of the tank where the current is constantly changing. It looks like a lot of wasted electricity to me, but there is a chance that with the help of the other pumps it keeps sediment from building up.

The back of that reef is basically moving in thee same direction constantly and produces nice growth to the frags I stick back there. I have a 20g without surge pumps. Just a return flow and a power head blowing right to left. It grows everything my 120 with the surge pumps will grow. It has reliable high, low and chaotic areas in it. I like the consistency.

I have 6 of what I call "G" spots (grow spots) in my 120 that seem to make pretty much everything SPS, Favites, and Blasto take off growing. The are all far from any direct source of water flow and all have consistent large volume water movement traveling in one direction. It appears to be paying off for me. I am not sure how my euphyllia would like it but my Caulastrea appears to have responded well.

The sump of my 120 has 4 SPS frags in it that live off of the spilled light of my Cheato grow section. They are a few inches from the return flow intake at the top of the final baffle of my sump. That area is as close to true laminar flow as I can imaging. It has only been 2 months but they appear to be doing well.

My current build is aimed at SPS and I am not planning to use surge pumps in it. Just tons of diffused directional flow. The plumbing is mostly done and I fired it up last night to see what things looked like and there are plenty of swirls and back eddies to keep food moving, polyps swaying and a really reliable flow to each coral. I am feeling pretty good about where it is going. So, yes. Laminar is where I am putting my new money.

 

[Brew12]

I feel there is confusion between laminar flow, chaotic flow, and coral needs. There are many studies talking about how laminar flows do not penetrate the boundary layer of the interchange zone of the coral. Chaotic flow reduces that boundary layer providing better exchange of nutrients and wastes. This has someone come to be taken to mean that chaotic flow in the water of our systems is better then laminar flow. That isn't necessarily the case. IMO, reefers should be worried about velocity and velocity is better achieved with laminar flows. If you get enough velocity the flow becomes chaotic when it hits the coral and reduces the boundary level to allow better waste/nutrient export.
If you have chaotic flow away from the coral, your flows are intersecting and reducing the velocity before it hits the coral. The result is that you get lower velocity at the coral and that chaotic flow will move around the coral in a more laminar fashion. This is the opposite effect of what we want.
I do think many people who run "chaotic flow" in their tanks actually have multiple high velocity laminar zones and so they get good results. As the powerheads change speeds, these zones shift through the tank ensuring every coral gets the high velocity laminar flow it needs. So these good results may not be for the reasons they think.

I could be out to lunch... maybe we can get @Sallstrom or @Dana Riddle to weigh in.

 

[MnFish1]

I'm not even sure laminar flow exists in our tanks. It might start out as laminar flow at the face of the powerhead, but once it intersects rock or alternate flow from another powerhead, it's now turbulent flow. For you to get laminar flow in a tank, it would have to be devoid of all structures, have but one powerhead, centered on that wall so the side walls didn't impact flow direction, and be so long the "reflective" flow off the far wall wouldn't happen. Look at that BRS video where they show Mr. McSparkles tank, and all the different directions those sparkles are going. These might be considered laminar flow powerheads, but the interaction of other flows make it turbulent flow.

I'll repeat, laminar flow doesn't exist in our tanks....or at least extremely difficult, if not impossible, to achieve.

This is the answer. There is no such thing as 'laminar flow' in a tank with objects in it. Every time a bit of water hits a rock - it disrupts the laminar flow - and by definition - its no longer laminar. Now - if you set a power head directly in front of a coral it would be hit by pure laminar flow - but it doesn't last long. Here is an interesting opinion from another article for those interested.

https://www.advancedaquarist.com/2006/11/aafeature/view?searchterm=water flow