Topic Of The Week # 1 - Water Movement
 

As we usher in the new year, you will see many exciting changes within the Zoanthid forum beginning with the return of Topic Of The Week. TOTW is a Bi-weekly thought provoking discussion with a direct impact on our reef tanks that will help achieve a better understanding of what is vital, critical and sometimes necessary to maintain a healthy, balanced and thriving ecosystem. It's success is based solely on your input and feedback on a daily basis. Some topics might sound elementary and some might seem advanced, but we hope you'll share as much and as often as you possible.

TOTW will be posted on Sunday. If you have an idea for TOTW, please forward your suggestions to our newest moderator Agu, myself and another member who will be announced this week.


TOTW # 1

Water Movement, unlike many other topics which are debated heatedly, this is one which the reefing community agrees upon as a vital component in achieving a prospering system.

1. How does Water Movement/Flow/Current/Turnover play an important role in your system?

2. Variable/oscillating or constant flow, which is better?

3. How is the above flow/current/turnover achieved in your system?

4. List the do's and don't as it relates to flow/current/movement?

5. Should internal flow and turnover be measured?


Don't reduced your replies to the 5 questions listed, lets discuss flow in its totality.

Mucho

For me, flow needs to be tailored to match the coral's requirements rather than meeting some magical number. There are a few standards, like the minimum of 10x turnover for a basic system, but there are some corals designed for tons of flow while others prefer a gentler amount.

In a reef tank, flow usually needs to be greater along the top, which is easy since very little is in the way to cause an obstruction. Medium flow occurs around the rockwork, and low flow usually happens over the sand bed because we don't want the sand blowing everywhere.

I am absolutely thrilled with my SeaSwirl! It hits every single inch of the tank, even around the overflow, which is in the middle (didn't really want one there but it was a great deal). I have the flow split in 2 & it bounces off the glass & back towards the tank. It even blows down the front glass to the corals on the bottom. It's all I need & doesn't stick out all ugly, like powerheads do. I do have some small powerheads on the back, so not too much detrius settles back there.

I have mostly constant flow provided by a Seio and a Koralia 4 placed at opposite ends of my 72 g "zoa-bow". I think the curved front helps with flow patterns and maintaining velocity. But... I also have a SCWD on my Mag 5 return but it's relatively little current compared to the current pumps. It changes up the pattern a little which I think is good.

I have had tanks with great flow and no flow and I have found that my paly's and zoas do MUCH better with a nice constant to erratic flow. I measure the amount of flow on how much the polyps move and how the skirt reacts. To me too much flow is the point to where the polyp struggles to open and the flow keeps it half shut. I feel like mine do best when there is a medium, erratic flow to where you can see the polyp every once and a while move on each side, but to where the poylp can stay open. Maybe even a slight constant movement.

When it comes to Palys and Zoas, flow/current and lighting are equally important, almost critical in my opinion. It's simply hard to have a thriving yet successful population of polyps without having them both in adequate amounts. So what's adequate? We had a heated discussion on another sight about the need to measure, (in numbers) the amount of flow in ones tank. It was said that low, med, high and very high flow was not enough to determine the proper velocity and velocity in numbers is what is needed. With this being such and individualized hobby, and we all have our own theories, some right and some wrong, here's my take and it never fails. You can push the envelope on flow only to the point of retracting polyps. Believe it or not, you can even acclimate polyps to a slightly higher flow then they are accustomed to if you do it gradually. Flow in all my systems over the years is simply enough random, oscillating or variable current which wiggles the skirts and the polyp. Yep, it's as simply as that. Mucho, that's dumb? No it isn't, understanding the reason current is so vital is most important.

The best description I can give in understand the vital role in water movement is the one I found on page 404 second paragraph of Delbeek and Sprungs Volume 3 of the Reef Aquarium.

“What’s important about the flow of water is what it achieves. Water motion brings food, facilitates the exchange of oxygen and carbon dioxide with the environment, and enhances the uptake and release of nutrients and waste. It does this by disturbing the boundary layer around a coral head/branch or any other creature”

Water movement also affords the polyps the opportunity to receive a balance of lighting as some may become shaded as they grow down, around and away from the face of the rock they are placed on. Inadequate movement of water in ones system can lead to polyp retraction, yep, it’s true. Over time, detritus can settle and accumulate between polyps. As this buildup continues over time, it can irritate polyps to the point where they are snuffed and less compelled to expand. This is why I use a power head once per month to blast each colony with direct current to clean, clear, remove and rid each colony of such build up. Try it just once and you will see all that flies off your polyps. It is one of the overlooked cause of polyp retraction.

The lack of water movement is also one of the culprits in coral bleaching, most often in hard corals. Adequate/increased water movement also helps heal corals that are already suffering from bleaching.

“Mucho, you’re rambling again”, ok, you’re right. If at all possible, I feel a variable/oscillating current which creates some turbulence is most natural and beneficial. Laminar (Directional flow), won’t hurt, I just feel that turbulent flow from at least 2 different directions is more beneficial and more natural. I achieve this in my system with a Mag 9 return attached to a SQWD. Not much current is generated from this type of return. I used/adjust the return nozzles just to hit places along the top/back of the reef. I have a simple set of Maxi 1200 on medium flow mods kits upping the flow to around 1450. One PH is hidden in the left corner blowing right and bouncing slightly off the left front glass and displacing that flow all over the right side of the reef. I do the same with the right side of the reef. Both power heads also create a nice water ripple along the water surface which help with oxygen exchange and evaporated cooling. I would characterize my flow as medium to medium high. Everything moves, wiggles and sways with a natural motion. Everything is Delbeek and Sprungs description in paragraph 3 above is achieved easily and inexpensively. Sure there are more efficient ways to get more bang and performance with controllers, wavemakers etc, and those are great avenues to achieve a thriving reef. I simply chose a cheaper means as zoas and plays not have the necessary high flow requirements as seen with SPS corals.

Sorry for the long rant.

Mucho

PS, it is very easy to determine excessive/too much flow. If the skirts are being blown over the oral opening, this is too much flow. If you are able to gently wiggle the skirts to the point that they won't retract, then you have found the optimal flow for your polyps. It's just that simple. Again, this does not hold true for SPS.

Great description. I'll have to reevaluate placement of some of my colonies and frags and maybe add a PH.

I have access to velocity meters and will think about how to accurately measure current velocity. The probes are not small enough to get inside a mat of polyps but I could capture data coming in, so to speak.

Just can't believe no one wants to share on this topic.

[QUOTE]I am absolutely thrilled with my SeaSwirl! It hits every single inch of the tank, even around the overflow, which is in the middle [/QUOTE]

pufferpunk, what size tank do you have? what's the gph going to your sea swirl? i have a 70g w/the overflow in the center and a wavy sea. i was reluctant to put my wavysea on it as i figured the overflow was going to block current to half the tank.

That is interesting Mucho. I have never tried to blow out the zoanthid colonies in my tank to remove trapped detritus. I'll have to try that and see what happens. (I'm pretty sure you'll be 100% correct.)

In tanks that have wave boxes or pumps that pulse to create waves, I bet the detritus is lifted out nicely.

On my own system, I've got three VorTech pumps. Prior to that I had two Tunze 6100s. The Tunzes had a controller that would alternately ramp up or down each pump, always at the opposite speed of its counter part. That worked nicely.

With the new VorTechs, I have all three running at about 2000 gph, maybe slightly higher. Each one runs in Reefcrest or Lagoon mode, which means the flow varies either sharply or smoothly (lagoon). I've got all three set to run completely independent of the other pumps, so that they can not communicate with each other. I feel that that is more random than not.

Once I find a spot that I like for each pump, I tend not to move it. Occasionally it may need a very slight adjustment as corals grow, but that's pretty much it. I have toyed with the thought of adding other equipment like the WavySea / SeaSwirl, but cost, more equipment, and electricity usage tends to sweep those thoughts away time after time.

Can anyone post some pics of their systems? :)

Sure. It isn't full of zoanthids like MuchoReef, but it has them scattered throughout my mixed reef.

[img]http://melevsreef.com/pics/07/12/fts_122107b.jpg[/img]

Mucho, let's see your tank!

Looks like you are a Vortec man.

No pics yet Melev. You have a very sweet tank btw my friend. Proof that hard and soft corals can co-exist

****CORRECTION****

I wrote

"It is very easy to determine excessive/too much flow. If the skirts are being blown over the oral opening, this is too much flow."

Why? Current blowing polyps that causes them to almost lay parallel to the substrate is too much as the thrashing of a polyp, ( A ) prevents enjoyment of the polyps aesthetically by the viewer/owner. ( B ) excessive current will cause the polyps to cup/retract.


I wrote

"If you are able to gently wiggle the skirts to the point that they won't retract, then you have found the optimal flow for your polyps. It's just that simple."

The reason I stated this is not because I'm a Marine Biologist, marine anything, nor do I have any formal educational training enough to make that statement. It was purely from many many years of setting up different systems and achieving the exact same results time and time again. I didn't want to mislead anyone into thinking that I have some crazy study or trials that support my statements. It was from simple observation only.

Thanks, Mucho

PS. good current is a major factor/contributor to skirt/tentacle elongation.

i now have a 45 gal rectangle tank opposed to my old 44 gal hex. I have a koralia 4 in it that makes zoas and palys in all positions of my tank wiggle, but not close. Its in the back right corner facing the front left.

no return flow because i have no sump.

thats right, im topless and bottomless but its working out great for me.

Mucho, I tried blowing off the zoanthids in my tank with a turkey baster, and all that came out was sand granules rather than detritus. I'm honestly surprised, because I fully expected to find trapped detritus.

Then you mut have some very good, or should I say, excellant current moving throughout your tank thus preventing any detrius from settling. I'm the one who needs more current, LOL.

MR

awesome tank[QUOTE][i]<a href=showthread.php?s=&postid=11528515#post11528515 target=_blank>Originally posted</a> by melev [/i]
[B]Sure. It isn't full of zoanthids like MuchoReef, but it has them scattered throughout my mixed reef.

[img]http://melevsreef.com/pics/07/12/fts_122107b.jpg[/img]

Mucho, let's see your tank! [/B][/QUOTE] `

I also agree that they like lots of flow. Whenever I put a few zoas on the side of my tank, which is partially blocked by rocks, they do not do as well as on my sand bed with open flow.

I have plenty of flow as I have sea swirl on my return, a vortech and three nanostreams on a controller. This is just my experience as there are more knowledgeable people on this forum.

I have what would be considered high flow for a zoanthid tank. 300gph Aquaclear and a 100 GPH powerhead on a ten gallon tank. That's 40X turnover. However virtually all the flow bounces off the front glass which disperses the flow.

[IMG]http://reefcentral.com/gallery/data/500/2DSCN3035.jpg[/IMG]

I also have Zoas in very low flow with marginal lighting and they look great. The flow is maybe 200 gph spread over 10 inches of weir and the zoas have covered the back and left wall.

[IMG]http://reefcentral.com/gallery/data/500/2DSCN2669.jpg[/IMG]

I suspect part of the flow requirement depends on where the colony originated.