Is shading BS?

[BoomCorals]

I had never considered how the structure of the coral could promote flow within itself. So many fascinating aspects to reef keeping!

I was just thinking that myself! There is so much science behind all of this. Truly fascinating.

 

[Dana Riddle]

This paper mentions coral feeding and water motion:
https://www.sciencedirect.com/science/article/pii/0022098195001565
It also mentions the boundary layer, where a thin film of stagnant water occurs around a benthic object. The lower the flow, the thicker the layer and diffusion can be potentially hampered.

 

[jda]

Although long out of fashion with the folks who tout flow GPH numbers like it is ***** size, a true wavebox will get flow and water between every branch, crevice, nook and cranny that flow pumps cannot reach and nothing is untouched. You get back and forth scrubbing 24x7. I will never have a tank without one... and that is saying something since I am calculating that the new tank will require 4x Tunze 6100s in a box to get a 1" wave.

 

[madweazl]

Although long out of fashion with the folks who tout flow GPH numbers like it is ***** size, a true wavebox will get flow and water between every branch, crevice, nook and cranny that flow pumps cannot reach and nothing is untouched. You get back and forth scrubbing 24x7. I will never have a tank without one... and that is saying something since I am calculating that the new tank will require 4x Tunze 6100s in a box to get a 1" wave.

I have a hard time understanding what you base things on most of the time you reply. What makes you believe that type of waveform leaves nothing untouched? I'm not sure which pumps aren't capable of generating that type of waveform but Ecotechs do it without issue as well. Additionally, what makes you believe a pair (or more) of pumps on opposite ends of a tank in anti-sync using a different wave-form aren't capable of leaving "nothing untouched?"

 

[jda]

Experience. There are some thing that you need to see for yourself and not just read about or watch on a video. Put a true wavebox on your tank - you could use a Ecotech for this and build a box - see the difference in the waves that they make. The difference is pretty amazing.

 

[Dana Riddle]

Although long out of fashion with the folks who tout flow GPH numbers like it is ***** size, a true wavebox will get flow and water between every branch, crevice, nook and cranny that flow pumps cannot reach and nothing is untouched. You get back and forth scrubbing 24x7. I will never have a tank without one... and that is saying something since I am calculating that the new tank will require 4x Tunze 6100s in a box to get a 1" wave.

I'm a big fan of Tunze products, and it has been my intent to compare calcium sulfate dissolution rates (the 'clod' method) when using a Wave Box and an appropriately sized propeller pump. I suspect the prop pump will beat the wave box, but if I knew the result ahead of time I could simply skip the experiment. But it really depends upon the animals being maintained and their water velocity saturation rates.

 

[mcarroll]

A coral colony large enough to self-shade also has the ability to restrict flow.

Precisely...my understanding is that this is their adaptations to surface-living....have to be able to break the incredible force of the water AND the incredible energy from the sun that exist there. Both amazingly destructive, so it's a pretty amazing set of adaptations.

I seem to remember that they can achieve something like a 60-70% reduction in light hitting them just by branching the way they do. (Pretty sure that was regarding an acropora.)

It would be interesting to know if it's a comparable amount of energy dispersion from water as well.

I've got a few intersting articles saved that at least mention the topic...

Is the coral-algae symbiosis really ‘mutually beneficial’ for the partners? is one of them.

Oceanic Forcing of Coral Reefs also has some really interesting stuff on water flow.

And although it's a tangent....if the function of coral shapes are interesting to anyone else, here's another one of potential interest:
Function of Funnel-Shaped Coral Growth in a High-Sedimentation Environment (This one also has nice tips on water velocity.)

 

[jda]

Dana - skip the experiment and use both. Inside polyp extension is much more significant with the wavebox and it does a great job of working debris both in and out of the colonies without letting it settle... then you need a flow pump to move it away. The same thing happens in the rock structure.

 

[Dana Riddle]

Dana - skip the experiment and use both. Inside polyp extension is much more significant with the wavebox and it does a great job of working debris both in and out of the colonies without letting it settle... then you need a flow pump to move it away. The same thing happens in the rock structure.

I'm a giant proponent of increasing water motion within an aquarium, but my experience with using only *a* Wave Box as the motive force resulted in failure of Porites corals to extend their polyps after a few months' time. I know of at least two other aquarists who were unable to maintain SPS corals for extended periods of time using only devices that generate oscillating water motion. Were these issues due to water motion or some other factor? That's the reason I feel the experiment has some merit. This idea has been fermenting for a while, see here:
http://www.advancedaquarist.com/2011/1/aafeature

 

[jda]

If you do decide to experiment, I would not treat them as mutually exclusive since there is no need in practice. Of all the people that I know who swear by wave boxes, they still have substantial flow pumps as well. If I had to choose, I would keep my flow pumps and get rid of the wave box, but it is impossible now that I have seen what it can do in combination.

 

[Dana Riddle]

If you do decide to experiment, I would not treat them as mutually exclusive since there is no need in practice. Of all the people that I know who swear by wave boxes, they still have substantial flow pumps as well. If I had to choose, I would keep my flow pumps and get rid of the wave box, but it is impossible now that I have seen what it can do in combination.

My goal is for hobbyists to maintain the highest rate of success, hence the experiments. Oscillating flow has been shown to promote the highest rates of photosynthesis in some turf algae species. Does the same apply to corals? If so, at what rate? I have no doubt that increasing water motion, up to a point, is beneficial. Glad to hear of your successes!

 

[mcarroll]

the folks who tout flow GPH numbers

...just haven't heard about CPS/FPS – aka flow velocity. (See: Tunze flow vs turbulence video)

Too bad it costs >$x,xxx to measure flow velocity.

Anyone have a used Swoffer 2100 setup for sale?

 

[mcarroll]

Oscillating flow has been shown to promote the highest rates of photosynthesis in some turf algae species.

Not quite specific to shading, but so-called flicker light (vs continuous light) apparently has a similar effect on photosynthesis.

Flicker Light Effects on Photosynthesis of Symbiotic Algae in the Reef- Building Coral Acropora digitifera (Cnidaria: Anthozoa: Scleractinia).
(emphasis mine)

At supersaturating light intensities, photosynthesis was less inhibited by flicker light than by constant light.

Due to the lens effect, light intensity in shallow-water environments sometimes reaches more than 9,000 [PAR], corresponding to 300 to 500% of the surface light intensity (Schubert et al. 2001, in shallow estuary).

 

[Dana Riddle]

...just haven't heard about CPS/FPS – aka flow velocity. (See: Tunze flow vs turbulence video)

Too bad it costs >$x,xxx to measure flow velocity.

Anyone have a used Swoffer 2100 setup for sale?

That's relatively inexpensive. The Marsh-McBirney Flo-Mate 2000 I have was 5 grand when I bought it in the late 90's. That model has been discontinued and its replacement is much more. The clod method only costs a $100 or so, including the purchase of the scale.

 

[Dana Riddle]

Not quite specific to shading, but so-called flicker light (vs continuous light) apparently has a similar effect on photosynthesis.

Flicker Light Effects on Photosynthesis of Symbiotic Algae in the Reef- Building Coral Acropora digitifera (Cnidaria: Anthozoa: Scleractinia).
(emphasis mine)

http://www.advancedaquarist.com/2006/5/aafeature
I must add I haven't read the reference mcarroll posted. Too late in the evening for an old man (me.)

 

[McMullen]

The effects of light and flow on photosynthesis are not mutually exclusive. A coral colony large enough to self-shade also has the ability to restrict flow. I published this info back in the 90's when Aquarium Frontiers was still around, but here's a primer. Coral colonies (or any benthic object for that matter) restrict flow and create an area of high pressure (such as a ship's bow creates high pressure when moving through the water. Of course, for our purposes, it is flow moving against a stationary object.) Water moving over the top of the colony picks up speed and creates an area of low pressure (according to Bernoulli's Principle) hence water moves from the area of high pressure upwards to the area of low pressure. This is the reference:

Chamberlain, J. and R. Graus, 1975. Water flow and hydromechanical adaptations of branched reef corals. Bull. Mar. Sci., 25(1):112-125.
Crude drawing of the principle:
I'm of the opinion that crashes of mature coral colonies in aquaria are due to impacts of poor flow and, yes, light (but to a lesser degree.)

That's great! Certainly makes since. However, once again, this "phenomenon" is in fact taking place in mine and others tanks. My coral is above rock work. There are yellow polyps at the corals bottom edge in constant movement. Therefore, flow in my case, is not the issue. Not even a small part.

 

[mcarroll]

http://www.advancedaquarist.com/2006/5/aafeature
I must add I haven't read the reference mcarroll posted. Too late in the evening for an old man (me.)

Love it!! Thank you for posting it!!!

(I suspected you might have one up your sleeve for that. Busy busy! )

For ref (to others), my link is a just reference to a 2008 article on the topic that someone else wrote.

Dana's is a real article that HE wrote.

I'm sure I read it back in the day too but gonna have to do a re-read now!

 

[leepink23]

I still think we're getting too hung up on the light source verse the shading itself. Shade is shade right? If PAR is equal in the shaded areas (impossible to know in these examples but they're both obviously shaded), what does it matter if it were created by T5/florescent, MH, LED, or the sun?

Why are these two corals growing into areas of shade...

... but this one isn't?

What is responsible for that difference and how do we promote it to continue happening? I don't use amino acids, phytopheast, or any other products in the tank. I don't set wavemakers to feed mode, I don't turn off the skimmer, carbon reactor, or return pump. I generously feed LRS (Reef and Herbivore Frenzy) twice a day; it takes about five minutes for the food to be consumed by the fish and/or sump after a feeding.

I tried getting a decent picture of the underside, there is still growth there just not in the one spot, makes me question flow? Also I feed reef refrenzy and apex pellets which have coral food every day. I run a skimmer and scrubber but no other filtration.

 

[madweazl]

Experience. There are some thing that you need to see for yourself and not just read about or watch on a video...

Is this like your experience with Joshi's and Paletta's tanks, or yours?

 

[alton]

I can vouch for JDA, plenty of experience. On the Tunze Wave Box I had the large one on my old 300DD and nothing moves water like it. I dropped a bunch of Coral Frenzy on the opposite side and it was amazing how the fine particles moved across the tank. I use Tunze and Ecotech MP40 /10's power heads and there is/was no comparison. But my frogspawn did not like the movement so I traded it off. Great topic and thanks madweazl for starting this thread.