Sodium Thiosulfate

[Cakepro]

Hi Randy ~

I was given a quantity of 30% sodium thiosulfate for dechlorinating brine shrimp cysts after decapsulating them with household bleach. I would like to know if thio works immediately or if I need to wash/rinse the cysts for a period of time, and if so, how long is too long? Also, I know this is a pretty strong solution so how do I cut it (how much thio to how much water) and what type of water should I use (sterile, RO, RO/DI, tap, etc.). Is thio potentially harmful to the cysts if it is not diluted enough when using it? I pour in a tablespoon or so to a gallon of water and swish the cysts in it for a few minutes, which I'm sure is overkill, so that's why I'm asking you. :) I get plenty of hatchlings but I'm not sure the hatch rate is actually 90%, which is the grade of cysts I bought.

Many thanks,
Sherri

[Randy Holmes-Farley]

You are concerned about chlorine in the cysts themselves, or the water surrounding them?

[Cakepro]

In the cysts themselves as well as in the surrounding water, since the cysts are kept moist in the fridge in the water in which they are rinsed.

[Randy Holmes-Farley]

I don't actually know how long, or how effective thiosulfate will be in dealing dealing with chlorine (hypochlorite) that has gotten down into the organic parts of the cyst. I'd probably give it 5 minutes, then get rid of the thiosulfate water somehow.

I don't know how toxic it might actually be to a cyst.

Time for you to experiment, I think. :D

[rsman]

id have to dig around, but as I recall when it comes to artemia chlorine isnt really *that* toxic, considering they do fine in ammonia as high as somewhere in the 150ppm range :D the concentration of chlorine needs to be strong to cause harm, along the lines keeping a low chlorine level in a artemia grow out tank will keep bacteria from growing, you want the bacteria there so they can eat it, but you dont want the bacteria to start consuming the oxygen.

now how much of that hangs around to be consumed by your target fish, I donno!!!

[Randy Holmes-Farley]

I wouldn't worry about significant amounts transferring to fish if the brine shrimp live for a few days. :)

[Cakepro]

I'm sorry I wasn't clear in my post. My primary concern is nuking the decapsulated cysts with too strong of a dose of thio (hence my questions about how to cut it). I already know that the hatched shrimp are fine, but my hatch rate is not 90% ~ which is why I asked specifically about the thio.

~ Sherri

[Randy Holmes-Farley]

Ah, OK. I'd use the normal dose for dechlorinating tap water, but I don't have such numbers handy.

Anyone have them available? Boomer?

[rsman]

i had to search

on an interesting note "residual chlorine attaches to decapsulated eggs" and "chlorine may be transfered to hatching medium" tells me that even though the artemia will live, your fish may or may not be harmed ??????

washing cysts in .1% solution for 1 minute will remove any residual chlorine and not harm cysts.

[Cakepro]

Excellent ~ just what I was looking for. Thanks!

~ Sherri