So I'm sitting here with an empty stirrer and rereading the entire thread to see what I can pick up on. Here's my thoughts for the evening.
I had my best hatch with about 90% FRESHLY mixed water. Ed may have caught onto that already as he mentioned using freshly mixed sterile water in a PM (it's on my TO-DO list Ed!)
I'm thinking about how the kriesel really works..centripital and centrifugal force and got off reading up on my physics...definitely some conficting information out there. Anyway, in a nutshell, if you start stirring things up they want to "stay the course" and go off on a tangent (sure, pun intended if you like). What's keeping the eggs from running into the sides of the "kriesel" type setups? Technically centripital force. Start them spinning up and you get the virtual "centrifugal force" that wants to pull them off on the tangent. The balance is what keeps them in circulation.
Here's the interesting parts...since I'm dealing with loose eggs, they have to be swirling pretty fast to overcome gravity wanting to pull them all to the bottom..well they're slightly positive boyancy helps counter gravity. What I can't quite put my figure on is what produces the "centripital" force that prevents them from hitting the sides of the kriesel? It's not like we're "swinging a ball attached to a string" where the mechanical attatchment of the string is what's keeping them in circular motion...it must be coming from something else. The best I can come up with is the water itself acting somewhat like liquid ball bearings between eggs that come close to the hard surface of the bowl. But again, what I'm NOT seeing within the kriesel is the concentration of the eggs, larvae and food items in the CENTER of the circular motion created by the kriesel. Ideally that's what we'd want, right?
The best thing I can come up with is looking back at Jason's kriesel design that used a slow water feed into the bowl. This created some water movement within the bowl...adding it at the edges and exiting the kriesel at the center hole. This has me thinking...the current of water moving from outside to center while in a circular motion may generate more centripital force than centrifugal force, thereby concentrating more of the eggs at the center area. If I perhaps make ANOTHER kriesel with openings on BOTH sides and use a REALLY FINE MESH (could use some help sourcing that) then perhaps we could acheive the perfect concentration of eggs in the center of the kriesel...the only concern being the flow rate THROUGH the kriesel would have to be very low (perhaps the minijet at it's lowest setting will work).
Granted, I'm doing a LOT of thinking on something that SHOULDN'T have to be so complicated. In Sadvoy's article that I cited a few weeks back in the thread, I reread it and noted that while the details are not specific, to some up their hatching method they basically dumped the eggs in an aquarium with an air feed, that was it.
Then there's the matter of the eggs ending up on the bottom. It was proposed earlier that maybe, prior to hatching, their bouyancy changes? Perhaps if the eggs start to sink in preparation for hatching that could be part of the problem...i.e. they get stuck on the bottom and fizzle out right before hatching.
All of this thinking 'cuz I simply want 100 or 200 larvae to try to raise instead of 1 or 5!
And then there's the whole other issue of WHY air would cause problems with incubation! I'm still not really sure I get it. Maybe airstones are the ticket here? From my experience, we know that air driven circulation CAN work, but why MIGHT RSMAN, Mai and others suggest the propeller-style stirrer as a BETTER alternative. We definitely get a different circulation pattern that is perhaps more natural. I'm also willing to consider that perhaps I got the air flow *JUST RIGHT* in that one successful hatch and haven't duplicated it since.
We also know that the powerhead driven stirrer works, but in my initial design it's not that efficient and difficult to set up, work with and get babies out of.
I ALMOST wish it was a fertility issue..that's something I could understand!
Keeping my fingers crossed for that next spawning and hoping the stirrer does the trick. If I get another dozen spawns or so I should know more...right?
Feeling like Dr. Cambell in "The Medicine Man", at least when it comes to hatching my mandarins!
MP
Whatever gets me there, that's good enough for starters!
