Re: [Killietalk] RE: Hatching brine shrimp

[Wright Huntley <whuntley at verizon_net>]

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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