How toxic is formalin to plants?

[Mean_Chlorine]

I've got a nasty mystery disease in one of my smaller aquaria; I
suspect it's some sort of parasite, but it doesn't respond to normal
treatment.

I've have decided to tear the tank down and restart it. The fish will
get a formalin bath and then spend a few days in quarantine, and I'll
replace the sand, rocks etc, and clean the pumps with chlorox - but
what can I do with the plants?
I'd like to keep them.

I know one can sterilize them with chlorox, but I also know that the
plants take a lot of damage - so how about formalin? Would the plants
survive an hour-long bath in 150 ppm formalin (same as I'll use for
the fish)?

My guess is that they'll handle formalin a lot better than chlorox -
but does anyone know for sure?

How toxic is formalin to plants?

[NetMax]

"Mean_Chlorine" > wrote in message
om...
> I've got a nasty mystery disease in one of my smaller aquaria; I
> suspect it's some sort of parasite, but it doesn't respond to normal
> treatment.
>
> I've have decided to tear the tank down and restart it. The fish will
> get a formalin bath and then spend a few days in quarantine, and I'll
> replace the sand, rocks etc, and clean the pumps with chlorox - but
> what can I do with the plants?
> I'd like to keep them.
>
> I know one can sterilize them with chlorox, but I also know that the
> plants take a lot of damage - so how about formalin? Would the plants
> survive an hour-long bath in 150 ppm formalin (same as I'll use for
> the fish)?
>
> My guess is that they'll handle formalin a lot better than chlorox -
> but does anyone know for sure?
>
> How toxic is formalin to plants?

I think that Formalin is the trade name for Formaldehyde (as example,
when used as a carrier with Malachite green, for Ich products). I don't
notice any plant damage when I use formaldehyde at a prescribed dosage of
1 drop per US gallon using a standard 37% solution. I've been told that
the noxious effects mostly evaporate in 20-30 minutes. I don't know how
my dosage compares to your 150 ppm. I'd need to get mine into mg/l and I
don't even know the drops to ml ratio.

I have used the Krib's 20:1 water:bleach dip followed by de-chlor rinse.
Thick leaved plants (Anubius, Amazons, Crypts etc) were unaffected by a
30-60 second soak. Fine-leaved plants only got a short 10 second dip,
and seemed ok after (though not as unaffected as the thicker leaved
plants). Many of the fine leaved plants are fast growers and go through
die-offs when stressed anyways, so I have no compunction about throwing
lots of these out.

I hope your contagion is not an internal parasite. Good luck.

--
http://www.netmax.tk/

[Limnophile]

Just a side note, formaldehyde is the name of the active ingredient.
Normally it's a gas. Dissolve it in water and you have formalin. It's a
known carcinogen as well as being somewhat toxic, so be sure to wash your
hands after using it.

Limnophile

[Mean_Chlorine]

"NetMax" > wrote in message >...

> > How toxic is formalin to plants?
>
> I think that Formalin is the trade name for Formaldehyde (as example,
> when used as a carrier with Malachite green, for Ich products).

Yep, that's the one.

> I don't
> notice any plant damage when I use formaldehyde at a prescribed dosage of
> 1 drop per US gallon using a standard 37% solution. I've been told that
> the noxious effects mostly evaporate in 20-30 minutes. I don't know how
> my dosage compares to your 150 ppm. I'd need to get mine into mg/l and I
> don't even know the drops to ml ratio.

Hmmm... That'd be, about, 1/15th ml per gallon, meaning... where's
that calculator... roughly 18 ppm.

That may be in the right ballpark, as this website,
http://edis.ifas.ufl.edu/BODY_FA041 , cites "15--25 mg/L (2
drops/gallon or 1 mL/10 gallons)" as usable for prolonged (indefinite)
immersion.

The dip the fish will spend 30 minutes in, and which I'm thinking of
letting the plants spend perhaps 10 minutes in, will then be about 8
times stronger.

> I hope your contagion is not an internal parasite. Good luck.

Thanks. I'm increasingly convinced it isn't something internal. I've
added one ml of formalin to the tank, translating to about 13 ppm
initially, and the fish visibly improved in just a few hours.

According to articles on another site,
http://www.fao.org/fi/eims_search/simple_s_result_1252.asp?lang=en ,
most of the formalin is probably degraded within 36 hours, but I'm not
going to repeat the treatment - there's shrimp and snails in there.
Plus the formalin of course kills the filter bacteria. I just needed a
stopgap measure to buy me some time, and it seems to have done that.