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RE: [Killietalk] RE: Hatching brine shrimp
Wright,
You bring up some very interesting points. I had the Salinity so high
to help the separation of shells and bbs. But maybe that is really less
of an issue that I was thinking, especially since increased salinity
reduces/delays hatching (which I didn't know). I'll reduce the salinity
and see what happens.
I will also have to try wetting the eggs for a bit first. That might
work well, and is a lot easier than decapping the eggs.
My water is extremely soft, though neutral (from the tap). I was adding
in Epsom salts to help with this, but not at great quantities. I should
measure the hardness.
The cysts I got are from the Great Lakes, and they suggested 82-86DF for
hatching (which I missed when I first started this whole process). So I
think at 86DF would be about right for me. As I said, it is already
producing better hatches than 80DF.
You've definitely given me more food for thought. Thanks for the great
input.
Mark
-----Original Message-----
From: killietalk-bounces at aka_org [mailto:killietalk-bounces at aka_org] On
Behalf Of Wright Huntley
Sent: Friday, January 02, 2004 1:43 PM
To: killifish discussion list
Subject: Re: [Killietalk] RE: Hatching brine shrimp
Mark Pearlscott wrote:
> I'm currently using water that is:
> 86DF in temp.
> 1.029 in Salinity (specific gravity)
> pH above 7, but currently not measured. I need to do this.
> Light on it 24 hours a day.
Lowering the salinity usually will speed the hatch. You do not need
ocean salinity to get good hatches, IME. The bbs seem to be able to
survive in very low salinity water -- some say just water-softener water
has enough salt. :-) Hatching at lower salinity shocks them less, so
they may even last longer in the tank. IDK for sure on that.
>
> Hatching (within 24 hours) seems better since I raised the temp. I
have
> run a few batches longer than 24 hours and of course more hatch out...
> but still trying to get a good 24 hour hatch.
Heat, salinity, and *above all* egg (cyst) quality determine the hatch
percentage and timing. I feel light helps, but not all agree with me on
that. Tests at SF Bay Brand and elsewhere do indicate that hatching is
photosensitive.
Salt Lake cysts need more heat than SF Bay eggs, IME. Some Asian eggs
are a real pain, and hatch over 3 days no matter *what* you do. ;-)
>
> So... Next I have to measure the pH of the hatching water and adjust
to
> above 8, and then I will also try decaping the cysts after that.
> Eventually I should end up with really good hatches. I can see that
> just by adjusting the temperature the hatching is better.
Above 8 is less important than good solid buffering. Sodium bicarbonate
will hold it in the high 7s, but it will be hard to get over 8 without
something more alkaline. Some alkalis (NaOH, CaO) can raise pH but may
do nothing to buffer the water. What you need is moderate to high KH, so
pH isn't too squirrely as organic debris builds up.
I have never been able to improve hatches of either good or poor eggs
with decapping. In fact, I suspect I reduced the hatch rate most of the
time. YMMV.
>
> Ultimately it is another learning experience.
>
Yep. And all we can do is give guidelines that work for us. You will
still want to tinker to make *your* conditions work best.
The biggest difference I have found is that hard tap water is well
buffered and nothing but NaCl is needed. Soft water, OTOH, suffers pH
crashes as bacteria build, and everything turns slimey and stinky, if
some baking soda and/or some Epsom salts aren't added. [For folks with
soft water, regular reef salts are well worth the extra cost, I think.]
Another problem is using too much salt and slowing the hatch rate
dramatically. BTW, note that eggs do not really wet well in salty (or
even hard) water. It pays to wet them with a bit of DI or RO water to
get short hatch times, too. I just put eggs and a few ounces of RO in
and let them bubble while I go get out the salt. I add all the fresh
water as they bubble and then add the salt last. I perceive this as
cutting that hatch spread at end of hatch. All hatch more at the same
time, I think. I don't do the full 15 minute soak the suppliers suggest,
as I would surely go off and forget it, if I did. A minute or less seems
to work about as well.
Maybe it's a bit like the first rains washing the cysts back into the
salt pond or lake. The low tds rain starts the hatch process but the
salinity then slows it to allow proper nauplii development.
Wright
--
Wright Huntley -- 760 872-3995 -- Rt. 001 Box K36, Bishop CA 93514
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