How long does GC stay active?

[jasonrusso]

When I dose GC, I usually put the GC in a jar with RO and I shake it up several time during the day.

Well, the fish I was going to treat didn't make it. I got a new fish and I still have the GC in the jar. Is it still good to use?

 

[Big G]

Great question.
Without stabilizers in the mix, I would have some doubts that the meds would retain their effectiveness. The liquid versions of Prazi and Metro all have some sort of stabilizer to maintain shelf life.

 

[jasonrusso]

So I guess no one knows. I was going to dose a 55 gallon tank. I don't have enough left to dose the 20gal I am using now without buying another box.