Simple questions about SMB and Sulfamic.

[1mysurveymail]

Does SMB (Bonide Stump Remover) go "bad" if unsealed, stored, in the original container after ~2 years? It seems to be a solid mass.

Do sulfamic acid crystals (grout cleaner) go bad after being stored in the original container after ~2years?

 

[Martijn]

I bought my SMB 7 years ago and it still works (fine?). I just shake the clump in the container to get some powder.

 

[1mysurveymail]

I bought my SMB 7 years ago and it still works (fine?). I just shake the clump in the container to get some powder.

Thank you.

 

[Geo]

Sodium metabisulfite will decompose to just sodium sulfite when it's unsealed and exposed to the air. In the original form, it will produce SO2 when added to water alone. Sodium sulfite will too but to a much lesser extent. It will still produce SO2 when added to acid. As long as it's not dissolved in water, it should be okay. I know people who intentionally spray SMB with a water bottle so that it can be molded into balls for easy use. I would rather keep mine dry.

Sulfamic acid is slightly hygroscopic and will absorb some moisture from the air. As long as it is capped, it should be okay. Sulfamic acid can be dissolved and dehydrated back to crystals unchanged.