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Re: Water for daphnia and How to keep brine shrimp warm

Tomoko wrote:

> Date: Thu, 1 Mar 2001 21:04:39 -0600
> From: "Tomoko Schum" <tomokoschum at earthlink_net>
> Subject: Water for daphnia
> 
> Can anyone recommend how to prepare water for
> daphnia?
> 
snip...
> ... Two
> hours later, I found all of the daphnia dead.
> 
> I suppose the water was not suited for them.
> But I don't think my water is very high in
> chlorine, chloramine or heavy metal.
> Sometimes I forget to treat the water in
> which I hatch brineshrimp eggs, but the bbs
> hatch and live for a few days without a
> problem.

bbs are not very sensitive to chlorine, but Daphnia can be. What is worse,
in these days of chloramine, the usual products used to trap the ammonia are
deadly to many inverts and will kill Daphnia quickly.

If you treated the water with Amquel, Prime, o/e, that would be enough to do
it.

Counter-top filters are essentially worthless. You *can* get rid of chlorine
and chloramine with a pressurized cartridge filter. For small amounts, the
small ones in ice maker kits will work if you *very slowly* trickle water
through them. [Use a chlorine test to check that you are giving the water
enough contact time with the carbon to remove all of it.]

> 
> Anyway, I am getting another batch from the
> vendor that should arrive on Monday.  So how
> should I prepare water for them?  I can go
> ahead and age the water that the first batch
> died in, or I can use rainwater that has been
> collecting in a bucket on my back deck
> through the winter.  

Too soft, by far, for Daphnia. They like harder water, so add crushed coral
or calcium bicarbonate to their water if you have soft water out of the tap.
Also, be sure you change the water very gradually that first time.

If you have tap water with very low dissolved solids, such as is found in
San Francisco and Oakland, dumping fish or any animal directly into it can
cause osmotic shock as the soft water rushes into the cells and even bursts
them. Slowly drip the new water into the old, over several hours, until
volume is tripled, to avoid this problem. Give the organism a few hours to
adapt the osmoregulatory cell membranes to the new water.

> Alternatively, I can go
> to the supermarket and get Evian to be sure
> of the quality.

ROTFL! :-) :-) Folks *still* pay more than the price of gasoline for
substantially inferior water to what they can usually get right out of the
tap.

How quickly folks forget the "benzene in Perrier" stories!

Use your tap water. If it has chloramines, then use a trickle-rate
water-line carbon filter for any water that you don't want to kill
invertebrates.

Another trick for chloramines is to use one of the old photographer's hypo
type dechlorinators, like Novaqua, and then vigorously aerate the treated
water for another day to remove the deadly burst of ammonia that is
released, when they "break the chlorine-ammonia bond." [Aeration on plain
chloramined water is a waste, for it has a half-life of about 5 weeks.]

> ------------------------------
> 
> Date: Thu, 1 Mar 2001 22:24:34 -0600
> From: "Tomoko Schum" <tomokoschum at earthlink_net>
> Subject: How to keep brine shrimp warm
> 
> I am currently hatching brine shrimp at room
> temperature (70 degree F during the day, 62
> degree F at night) in 2 liter coke bottle
> hatchery.  I would like to raise the
> temperature to accelerate the hatching.  Can
> someone recommend a suitable method for this
> type of hatchery?

I use the same size hatchery, but keep it around 82F with a nearby lamp in a
large aluminum reflector (about $5 at WalMart). The extra luminance is a big
help in getting a high-percentage hatch, as the eggs are somewhat
photosensitive and need brilliant (2000 fL) light for best hatch, anyway.
Space the lamp to control the temperature. 60W shining at the side, from a
foot or two away, should be adequate. I even have used PC lamps to do it in
warmer weather, cutting the heat back, while keeping the needed light high.

Since bbs absorb the yolk energy and start molting about 6 hours after
hatching, their nutritional value drops significantly. If you don't get a
fast hatch (I like 24 hrs) the collected nauplii are a mix of rich and not
so rich ones. BS eggs are too expensive, now, to throw away that food value,
IMHO.

Wright

-- 
Wright Huntley, Fremont CA, USA, 510 494-8679  huntleyone at home dot com

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