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Re: [Killietalk] hatching brine shrimp
Hello Curt, After reading what you apparently got out of that brine shrimp
lecture, and noting the few responses to your post, I find I have to give you
a reply (even though I seldom post here) in hopes it will fill you in on a few
things it appears you missed.
First of all, yes the surface area of course does have something to do with
how much BBS will hatch and survive, just as it dictates how many fish any
given size aquarium can sustain; surface area controls gas exchanges. However,
there seems to be a missing critical factor here. In hatching BBS, it is
imperative that aeration be used, not only to constantly turn over the water surface
but to keep the BBS (cysts and hatched shrimp) in suspension. This is needed
to prevent suffocation which would otherwise occur if the BBS were allowed to
pile up on each other at the bottom in the absence of this water movement.
Of necessity, such a hatching vessel for BBS must have its airstone at its
lowest point, and therefore this vessel itself must have a one central low point
to facilitate this airstone. This, to keep the eggs in suspension as they
continue to fall to this central low point. With this in mind, flat bottomed
shoeboxes and trays cannot hatch and support a larger quantity of BBS and is not
more successful than a narrow-bottomed vessel, as you are suggesting, since
there isn't any low point where an airstone can be employed to keep the falling
eggs (cysts) in suspension; the eggs will merely fall to the sides. What you
are saying is true -- only if there were no aeration being used in any of the
vessels, but the lack of aeration seriously cuts down on the amount of BBS
one can hatch.
Its is for this reason that pyramid cone BBS hatchers are used, and not its
large surface area, even though that feature is a distinct benefit. The
narrowed bottom presents the central point where the airstone can be used to keep
the eggs circulating as they continually fall towards this central point.
Having the eggs constantly in suspension allows for more eggs to be used than by
having them in a flat bottomed container, with or without aeration since this
tray (or shoebox) will not allow for an airstone to keep the eggs suspended.
While you don't give a capacity of you plastic pop bottle, I'm assuming its a
2 liter bottle, with a diameter that I've come up with at 4.25" (or I guess
your 4.3" measurement?). Figuring on 4.25" this bottle has a surface area of
13.35 sq. in. These bottles are normally inverted, with the bottoms (now
"tops') cut out. The narrow neck now at the bottom allows for the needed central
low spot for the airstone, which is why this method is so popular.
The one gallon pickle jars have a diameter of 6.125", or a surface area of
nearly 19.25 sq. in. However these cannot be inverted. The recommended method
of use for them is to tilt them (in a wooden shelf with 5.875" diameter
cut-outs) which then presents a central low spot towards one side, into which you
place your airstone. Tilting these jars, on approximately a 30o angle off
verticle, will expose more surface area resulting in nearly 26 sq. in.
Your square shaped 12" x 12" (144 sq. in.) inverted pyramid, having the most
area, is obviously the best way to go for hatching larger quantities, but not
only because of its surface area. Its large, three gallon capacity, is
naturally going to let you hatch all that much more BBS (over the capacity of 2 ltr
or 1 gallon) and will be equally more successful than shoeboxes or trays, as
will any other methods outlined above. I've seen 5 gallon carboys (water
cooler bottles) -- 10.5" diameter, 33 sq. in. -- used with near equal efficiency,
since its both the capacity and the aeration, in addition to the surface area
that results in the success of your hatch. Ray Wetzel #08273 </HTML>
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