Water storage of research chemicals

[Rush]

I was thinking about storage and stability of research chemicals in liquid form:
is best alchool or water?

and if water, tap water is that harmful? there is chlorine inside, that's an onxidant, but its in a low concentration...

and demineralized water is the same of distilled water?

SWIM's FOAF has a couple of tryptamines(AMT in particular) solved in tap water and stored in a dark place. their stability is in danger or he should'nt much worry about?

and if its that bad, what can he do to improve stability?

SWIM thougt about adding alchool, in order to double the volume of the solution, as he heared from many parts that alchool is more stable.

thougts?

thanks