Help from a chemist type, please

[LizStreithorst]

I ordered Soduim Thiosulfate a good while back.  I found a good price so I ordered 10 lbs of it.  I mixed a pound of it in a hot water.  It didn't make the hot water get cold like my other Sodium Thiosulfate did, and the water mixture was a little cloudy, not clear.  I wanted to do a WC just now but this disturbed me and I looked on the sticker on the new stuff.  It said that it was Sodium Sulfate Anhydros, Food grade, 99% pure.  They sent me the wrong stuff, didn't they?  This will kill my fish, won't it.

[Mugwump]

I would say yes....what are you using it for?....

sodium sulfate anhydrous powder used as a filler in detergents...

Soduim Thiosulfate  is used as an industrial de-chloinator...and..

Sodium thiosulfate is also used:

    As a component in hand warmers and other chemical heating pads that produce heat by exothermic crystallization of a supercooled solution.
    In bacteriological water assessment, as it promotes the survival of coliform organisms by neutralizing residual chlorine.[7][8]
    In the tanning of leather
    To demonstrate the concept of supercooling in physics classes: Sodium thiosulfate, when heated, dissolves in its own water of crystallisation. This solution can be cooled to room temperature without recrystallisation. When crystallisation is induced by the addition of a small seed crystal, the sudden temperature rise can be experienced by touch.
    As part of patina recipes for copper alloys
    Often used in pharmaceutical preparations as an anionic surfactant to aid in dispersion
    As an ingredient to table salt, e.g. Sysco Corporation's small packets of iodized salt.

[LizStreithorst]

I'm using it as a declorninator only.  Luckily I had one more lb of the real Sodium Thiosulfate left, which gives me lots of time to find more.

Interesting to see it's other uses.  What I don't understand is that it is used to warm things up.  To use it as a dechlorinator I have to mix it first in very hot water because the Sodium Thiosulfate make the water cold!

Is there any use at all for this Sodium Sulfate Anhydrous stuff or should I just send it to the land fill?

[Mugwump]

http://chemicals.etacude.com/s/sodium_sulfate.php

[BillT]

Anhydrous only means that the dry form that you have a dry form of the solid material. Alternatively the dry crystals could have various numbers of water molecules associated with the sodium Sulfate crystals. This would affect how you weight out a particular amount of the chemical.

When dissolved in water, the sodium would dissociate to make a sodium ion (Na⁺), leaving the sulfate ion (SO₄^-).
This should act as a buffer. I think either sulfate or sulfite buffers are used in salt mixes. So probably not all that toxic in small amounts. Larger amounts might do weird things to your pH and might provide food for sulfur metabolizing microbes.

Sodium thio sulfate was used as fix in photographic processing. It was used to prevent ay further changes in a developed image by reacting with the chemicals in the paper or film emulsion. Its not much used for this anymore.