Method One:

Sodium Hypochlorite (5.25% Active-Household bleach)

1. 500 grams of cysts

2. 4.77 liters sodium hypochlorite

3. 75 grams of sodium hydroxide

4. 2.2 liters of seawater or freshwater

Dissolve sodium hydroxide in the 2.2 liters of water and allow the reaction to cool. Do not add hypochlorite until ready to decapsulate. Rehydrate cysts for 30-60 minutes in fresh water with aeration, drain and add cysts and hypochlorite to the sodium hydroxide solution. While stirring continuously, watch the color of the solution change from brown to grey to white to orange.

This should take from two to four minutes provided the chemicals were at full strength. When the orange color is detected, quickly pour the decapsulated cysts into a net or bag and rinse very well with fresh cold water. To assure the decapsulation reaction is stopped, have a solution already prepared of 0.1% sodium thiosulphate (Na2S203) and empty the decapsulated cysts into this container and stir around for 1 minute or two, rinse and than incubate.

I realize that 500 grams of cysts to start with is probably a bit much for the average aquarist but you'll have to do the math for the quantity you need for your particular situation. If you wish to decapsulate more than you need for one hatching, store the decapsulated cysts in a saturated sodium chloride solution and refrigerate and use as you need. You should be able to store one or two weeks cyst needs this way.

Method 2.

Calcium Hypochlorite 70% Active

1. 500 grams cysts

2. 325 grams calcium hypochlorite

3. 340 grams soda ash

4. 6.75 liters of seawater or freshwater

Divide the 6.75 liters of seawater or freshwater into two containers.

Dissolve calcium hypochlorite in one of the pails and the soda ash in the other half. Allow time for the insoluble percipatates to drop, then siphon off the clear portion (supernatant) and discard the precipatates. When ready to decapsulate, mix the two solutions together (carefully) and proceed as before. This procedure can take slightly longer, anywhere from 4-7 minutes. Deactivate chlorine as previously described.

Remember, these chemicals are reactive and a person should be very careful when working with them and use all necessary safety equipment such as goggles, old clothes and don't do this where spill could damage anything.

howard w. newman

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Date: 30 Sep 1997

From: wtctj@mail.zlnet.co.cn

To: Gilbert Van Stappen <Gilbert.VanStappen@UGent.be>