Does magnesium hydroxide smell sweet?

[Miami Reef]

First, my sense of smell is not good. It doesn’t work well.

I collected a piece of magnesium hydroxide when I dosed silica to my tank, and it rapidly dissolved on my finger tips. It smelled really good - like sweet honey.

Is my nose deceiving me, or does magnesium hydroxide have an odor?

 

[Miami Reef]

I smelled it after it dissolved on my skin.

 

[Randy Holmes-Farley Verified Community Expert]

You aren’t smelling magnesium hydroxide unless you created dust. It has no gas phase at room temp to be able to smell it. What you would be smelling are likely organic compounds associated with it for whatever reason.

 

[Miami Reef]

You aren’t smelling magnesium hydroxide unless you created dust. It has no gas phase at room temp to be able to smell it. What you would be smelling are likely organic compounds associated with it for whatever reason.

Thanks, Randy.

Will magnesium hydroxide irritate corals if it lands on them?

 

[Miami Reef]

Also, Can I dose my silica at night when pH is lowest to help the magnesium hydroxide dissolve as soon as possible? I think I read an article where magnesium hydroxide prefers a higher pH to dissolve? I want to make sure what part of day I should dose it for the best results.

 

[Randy Holmes-Farley Verified Community Expert]

Thanks, Randy.

Will magnesium hydroxide irritate corals if it lands on them?

Not sure, but I'd avoid it. The local pH is likely to be above 9 under a glob of magnesium hydroxide.

 

[Randy Holmes-Farley Verified Community Expert]

Also, Can I dose my silica at night when pH is lowest to help the magnesium hydroxide dissolve as soon as possible? I think I read an article where magnesium hydroxide prefers a higher pH to dissolve? I want to make sure what part of day I should dose it for the best results.

The magnesium hydroxide dissolves better at lower pH, and will form to a smaller extent at lower pH, so night or early AM dosing seems good.