Sulphuric acid sulphite replacement.

[Llamarama]

Hello everyone, I've been making parodinal with sodium metabisulphite and found it to work very well, if a little contrasty. I was using this instead of the sulphite as it's hard to get without going online.

I used to be able to get the metabisulphate as a fine powder, but now it's only available in tablet form which I have to tediously grind up now.

When I was looking into reversal baths for a side project that required concentrated sulphuric acid (98%) for the bleach, someone suggested using sulphite/metabisulphite instead as it's safer. My question is can I substitute the bi/sulphite for the acid, and if so, how much acid should I substitute per gram of sulphite?

 

[pdeeh]

You're getting a bit mixed up with your chemicals.

You can substitute Sodium bisulfate in the bleach, but that is not the same as bisulfite or metabisulfite.

the spelling is crucial!

 

[Llamarama]

Ahh, that explains why I was getting confused. I was working from memory and am quite tired. I'll go and talk to my local old style chemist, rather than the boots who insist I'm thinking of sulphate. Thanks for the pointer

 

[John51]

Sodium metabisulphite is used for home brewing as a steriliser. The home brew shops sell the powder in 100 gram tubs. (I'm in the UK.)

Catering supplies might have larger quantities if you can't order online.