Lugols Solution

[jacob.morgan78]

(I copied this over from the reef discussion forum due to no responses)

Does this stuff (lugols) go bad? I've had it for a few years (from my first tank) and dont dose iodine/iodide (whatever)... I want to add a few drops now because I just put in a few frags and thought it might help with healing... However, don't want to add it if it has gone bad or something... Not important enough to buy new stuff though.

Thanks!!!

 

[AquaticFins]

If stored in an airtight container in a cool, dark place it should be stable pretty much indefinitely...the shelf life would be measured in decades, certainly.

I've heard that the iodine will precipitate out of solution if the bottle gets too cold. Exposure to light will definitely break the solution down (you'll notice as it will lose its colour).

The rubber of the dropper on the bottle will become brittle and crack with age; the iodine comes out of solution as a gas fairly quickly if the Lugol's solution is left exposed to air.

In short, if it's only a few years old it should still be perfectly fine to use. It may have become a weaker solution if it's been exposed to extreme cold or heat, light or air...but it's not going to become unusable if it's just been sitting on a shelf for a few years. I would have no hesitations about using it in your case.

When the solution does break down, it seems the iodine mostly converts into hydriodic acid. It's a strong acid, but I doubt small quantities would be particularly harmful to an aquarium. I'm far from a chemist though, perhaps someone else can come along to explain what negative effects that may have in our tanks, if any.

 

[Randy Holmes-Farley]

I cannot see it helping with healing frags, but if the intent is as an iodine source, it is likely as good as it ever was (which IMO is not optimal, but many folks use it).

If you are thinking of it as a disinfectant, I do not think it will have that effect once diluted so much..

 

[jacob.morgan78]

Thanks!

If you are thinking of it as a disinfectant, I do not think it will have that effect once diluted so much..

Thanks for chiming in... I had heard/read/something that it could help (can't remember where)