Formalin

[sushi]

How do you know how old it is when you purchase it and what would happen if you used it?

[Duncan]

hi mate

we spoke earlier, basically there is no time limit on the formaldehyde the only caveat to this is cold and light

your cant freeze formaldehyde but Coldeven just chilly conditions will turn it to paraformaldehyde and light will cause the para to take in a milky appearance instead of a white floating precipitate even there all not lost there is a way back for it to a usable solution it will lose a bit of its strength but it would be ok to use again if in doubt pour some into a drinking glass its should look identical to water from your tap

so keep it a room temp and out of the light and its good for years

dunc

[sushi]

Thanks Duncan,
the koi are looking much happier with the fresh water too

[Duncan]

good man, always remember that when your out of options and ideas start changing water it can hurt and can put things right