Green Mandarin (Synchiropus splendidus) Breeding Log!

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Ok mwp, let´s test my english and see if I can add some thoughts.

The intention in this kreisel is to concentrate the eggs in the center of the spinning circle and it seems to be achieved with water going in, through a pump, making circles and out through a center hole, pushing the eggs to the certer. Right ?

Trying not to use a water pump, I was thinking if it was possible to push water through a center hole by an air driven flow on the outside. Like the water goes in through the bottom and out through the top in that cichlid kreisel. What do you think ?
We still would need two holes (in and out water flow) or just the pressure "on the out" would be enough two disrupt the flow inside the chamber and reduce centrifugal force ???

Just writting as it comes to my mind... little thinking on goods and bads of each thought. Just my 10th participation in this forum, so don´t mind if its just junk ! LOL

Anderson.
 
Anderson, I think you're understanding where I'm coming from...the movemovent of water through the kriesel via some sort of water feed and outflow would create more centripital force than the centrifugal force, thus bringing the eggs closer to the center of the kriesel. Keeping them more towards the center would reduce the incidence of them bumping the sides (if they in fact DO do that) as well as the risk of them coming in conctact with violent flows of air.

That's my physics theory for the day but it'll have to wait to get tested...the propeller stirrer is next in the batting rotation!

MP
 
I would think that the Kreisel acts as a weak centrifuge, and follows the same theory, well, ignoring any turbulence inserted.
 
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True, but in a centrifuge, how is material redistributed? Heavier stuff goes to the outside, correct? Well, as the eggs loose byoancy, they sink, and are denser than the water, right? So...they all start banging into the walls and such (just speculating here). The flow through of water from "outside in" might counteract that...

HMM.

MP
 
I think it's more complicated than that. When I swirl water in a small tub, the sand moves to the middle. For a commercial centrifuge, the acceleration is much higher, though. Hmm, interesting question. I suspect there's enough turbulence in a Kreisel to keep the eggs off the wall of the tank.
 
I would think at some point the designer of this thing made it work well, I would hope.

Maybe there is a precise flow rate that needs to be achieved for correct function.

In the Coral Dynamics Bangai Video. the eggs appear to stay clumped together in the center somewhat. Your eggs don't do that? I'm just curious.
 
Oh, I've long since ditched the cracked incubation thing...Mandarin Eggs FLOAT...their design just WILL NOT WORK for mandarin eggs, end of story. Well, maybe if I put some meshing over the outflow, but then all the eggs would just get stick in that.

Granted, the company will not return my email regarding return instructions....I'm REALLY PO'd with them at the moment.

I'm really focusing more on stirring/spinning designs like the Kriesel and Propeller stirrer - the "random turbulence" with "upwelling" created by that professional incubator is NOT going to function for mandarins.

MP
 
Tim, interesting idea. At minimum, even if not running, the flexible curtain could be used perhaps to fill the "gutter" that's in the foot of the bowl - this gutter "catches" and "holds" the cardinalfish eggs, and it may be a problem with mandarin eggs too! More experienced folks have some aprehensions about using air to circulate mandarin eggs - based on that running the air curtain wouldn't be ideal. I'd also suspect that the air rising in the middle of the kriesel might slow down or otherwise interfere with the vertical circular rotation (which most likely can't be good either). Still, it's definitely something to keep in the back of my mind for experimentation.

Jonathan's observation about SAND in a bucket is still haunting me - granted that's SAND, not eggs, and the density/bouyancy is a bit different between those two, but all the same, perhaps the stirrer WILL concentrate the eggs in the center afterall (although you couldn't tell that from the methelyne blue + propeller stirrer video). Perhaps there's some sort of inverse relationship between the amount of centripital force a spinning liquid can exert on a solid in so much as if the solid is denser than the liquid it is pulled to the center, but if it's less dense than the liquid it moves to the outside? Ah, a physics quandry.

HMM.

Matt
 
<a href=showthread.php?s=&postid=7514135#post7514135 target=_blank>Originally posted</a> by mwp
Jonathan's observation about SAND in a bucket is still haunting me - granted that's SAND, not eggs, and the density/bouyancy is a bit different between those two, but all the same, perhaps the stirrer WILL concentrate the eggs in the center afterall (although you couldn't tell that from the methelyne blue + propeller stirrer video).
Click to expand...
Same difference that homebrewers see when they get the spent hops to pile up in the center of the brew kettle.

If you start with a kettle of hops all evenly dispersed. After you stir it a bit, and let it gradually come to a stop, you can see the hops drift from the outer edge of the whirlpool towards the center.

I think what might be going on is that the material, eggs/sand/hops/etc, gives up energy to the water through drag. So as they slow down, they move to the lower kinetic energy regions of the water in the center of the whirlpool. You visualize the whirlpool as a series of concentric layers of water, with the different layers moving at different rates.

hmm.... I could have this backwards too. Been a while since I've reviewed my physics. But I do think it has to do with drag and a velocity difference.
 
ah... cool... cyclonic separation. hydroclone.

Here you go:

http://www.hydroclone.com/faq.htm

"Hydroclones are also related to centrifuges in that both are intended to separate heavies and lights by application of centrifugal force to liquids. The key difference is that Hydroclones are passive separators capable of applying modest amounts of centrifugal force, whereas centrifuges are dynamic separators that are generally able to apply much more centrifugal force than Hydroclones. "
 
EUREKA that is COOL Mr. Ugly!

In a nutshell, it sounds like my powerhead driven stirrer was more or less a hydroclone! Here's some of the interesting info I picked up:

"The Hydroclone is a closed vessel designed to convert incoming liquid velocity into rotary motion. It does this by directing inflow tangentially near the top of a vertical cylinder."

Score one for the powerhead stirrer - water comes in at the top, tangentally, in the vertical cylinder (in my case a 2 L pop bottle).

"This spins the entire contents of the cylinder, creating centrifugal force in the liquid."

Yup...

"Heavy components move outward toward the wall of the cylinder where they agglomerate and spiral down the wall to the outlet at the bottom of the vessel."

So in theory, eggs that go "dense" and sink will be thrown to the outside of the cylinder and drained off at the bottom. Maybe LARVAE would too?

"Light components move toward the axis of the hydroclone where they move up toward the outlet at the top of the vessel."

Herein' lies the difference...TWO OUTLETS in a hydroclone. I'd have to look at one's design to see how that all works, and in our case, we wouldn't want to drain off "light components" aka. boyant eggs!

VERY VERY VERY VERY VERY VERY VERY INTERESTING FIND Mr. Ugly!

Basically, the propeller stirrer, through its motion, should concentrate "light components" at the center of the bowl, keeping them off the sides. No wonder folks say it works. Granted, the kriesel should do this as well, concentrating lights on its axis, but I've never found a huge concentration of eggs at the axis in my kriesel.

Perhaps the REAL problem is that the difference between egg density and water density is VERY small....it takes several minutes for all the eggs to rise to the surface in the tank....they are VERY VERY SLIGHTLY positively bouyant. Given this small difference, it's not that surprising that the eggs just seem to stay in "orbit" following the path that the water takes in the kriesel. To this point, we've been assuming that the eggs shouldn't be allowed to maintain contact with the water/air interface (aka. surface)...maybe that's not entirely the case, or maybe there's just enough movement in the propeller stirrer to keep them slightly underneath the surface?

Time and experiments will tell...the mandarins look like they're gonna take their sweet time again before the next spawn...I've been watching them EVERY NIGHT but the tip off, the girth of the female, it's just not to 'spawning size' yet! I'm loading them with food to keep her makin' eggs!

MP
 
One word - "Centrifugal Gravity Separator" ;)

The only problem is we don't want to actually "separate" the eggs from the water!!!

Looking at the physics and real world examples there is definitely high hopes for the propeller stirrer, but in theory there should be a good chance for the kriesel. My NEXT step might be to make another kriesel that is powerhead driven and locate the exhaust NOT in the center, but instead on the outside edges, thereby concentrating the eggs in the center AWAY from the drains. This would also eliminate "air" as the driving force; not sure that "air" is the problem here, but a lot of other folks seem to think so.

HMM.

Matt
 
<a href=showthread.php?s=&postid=7516796#post7516796 target=_blank>Originally posted</a> by mwp
Basically, the propeller stirrer, through its motion, should concentrate "light components" at the center of the bowl, keeping them off the sides. No wonder folks say it works.
Click to expand...
That's how I see it.

<a href=showthread.php?s=&postid=7516796#post7516796 target=_blank>Originally posted</a> by mwp
Granted, the kriesel should do this as well, concentrating lights on its axis, but I've never found a huge concentration of eggs at the axis in my kriesel.

Perhaps the REAL problem is that the difference between egg density and water density is VERY small....
Click to expand...
Agreed. You can probably experiment with s.g. of your water to get a greater differential.

My frogfish egg rafts float at first and tend to sink as the eggs mature. I noticed that if I tried to reduce the s.g. according to the info from the clownfish breeders, the eggs sank much earlier. I stay with normal salinity now.
 
<a href=showthread.php?s=&postid=7516878#post7516878 target=_blank>Originally posted</a> by mwp
Looking at the physics and real world examples there is definitely high hopes for the propeller stirrer, but in theory there should be a good chance for the kriesel. My NEXT step might be to make another kriesel that is powerhead driven and locate the exhaust NOT in the center, but instead on the outside edges, thereby concentrating the eggs in the center AWAY from the drains. This would also eliminate "air" as the driving force; not sure that "air" is the problem here, but a lot of other folks seem to think so.
Click to expand...
The "real" kreisels have a slit water inlet tangential to the circumference and creates a laminar flow that generates the vortex as well as keeping the eggs from contacting the container, right? Exhaust is also through the cylinder wall, and behind a mesh screen.
 
Kinda been wanting to try a laboratory stir plate to create the circular flow.

Here's a DIY approach:

http://brewiki.org/StirPlate

Could even get a real lab unit and set it up with a temp controller.

There's a lot of cool stuff that can be adapted/adopted for use here.

Check out plastic conical fermentors... I keep thinking rotifer culturing container. The sloped bottom works really well for collecting stuff.
 
LOL, I don't think we want THAT MUCH stirring!!! Really not that much different from the propeller approach otherwise! I've seen those things stir...man how many RPM is it typically??? ;)

No spawning again tonight...they're gonna get a fast this weekend too so looks like it might be a while again...unless they go tomorrow (the worst possible day other than the weekend!)


MP
 
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