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Water From Dehumidifier?


  1. Water from dehumidifier?
    by krombhol-at-felix.TECLink.Net (Paul Krombholz) (Sun, 26 May 1996)
  2. Dehumidifier water
    by Anthony Zagar <azagar-at-MNSi.Net> (Wed, 22 Jan 1997)
  3. Dehumidifier water
    by Wright Huntley <> (Wed, 22 Jan 1997)
  4. Humidifier, was Re: New Fish Room
    by plasticolor/ (Thu, 12 Nov 1998)

Water from dehumidifier?

by krombhol-at-felix.TECLink.Net (Paul Krombholz)
Date: Sun, 26 May 1996

Michael L. Rapport <> wrote Friday May 24:

>  I was just wondering if it was posible to use the water that is collected
>by my dehmidifier which I run in my basement.Is it the same as distilled?
>Should I test it first? Is there any possibility it would harm my fish or

I would be very leery of using water from a dehumidifier because it
probably condensed on metal surfaces and could be very high in zinc or
copper.  I would collect some and test it by putting in a snail.  If the
snail lives and seems happy, then it is all right.

Paul Krombholz                  Tougaloo College, Tougaloo, MS  39174
In hot, humid 95 degree Mississippi

Dehumidifier water

by Anthony Zagar <azagar-at-MNSi.Net>
Date: Wed, 22 Jan 1997

Hello everyone,

I would like to express my concerns with using dehumidifier water to lower
ph and water hardness.  I used to do this when I was keeping P. ramirezi in
my tanks to lower the ph to a level of about 6.0.  I was never able to breed
them successfully and I just couldn't figure out why.  

Later, I discovered why when I was breeding fancy guppies (sorry but I love
the genetics).  I had a large pregnant female in dehumidifier/tap water mix
and when she gave birth to a very small brood (15fry) 50% were born dead,
two were born as Siamese twins joined at the stomach.  The rest were all
malformed too, all died two days later.  The first thing I suspected was the
dehumidifier water.  The female survived and was placed in regular tap water
and her next brood 33 days later was 43 fry, all which survived and I must
say turned out as exceptional.  

Warning!  I believe that dehumidifier water may in fact be toxic especially
to small fry. Adult fish can live in it but may not be able to breed
successfully.  I would be very cautious on using dehumidifier water,
personally I will never use it again.

Rain water or frost build up found in freezers is probably a better choice
if you have to go that way to lower hardness and ph.

I just want to say I've learned allot since I joined this mailing list.  I
have set up a 30 gallon (36" long) aquarium for apistos but I haven't gotten
any yet.  Still waiting to get the book Dwarf Cichlids (Linke and Staeck)
before I get any.  I'm also considering on getting another tank so I can
keep more of them.


Anthony         Windsor, Ontario Canada 

Dehumidifier water

by Wright Huntley <>
Date: Wed, 22 Jan 1997

Hi all,

Anthony described his very sad results using dehumidifier water. Others 
have gotten away with using it, but I believe it is *not* a good safe 
source, when purer water is only about $0.25/gallon at the store.

Many, if not most, dehumidifiers use copper coils for the condenser. 
The low-salts (essentially distilled) water that condenses on them is 
very corrosive, and may well pick up some of that copper. Topping it 
off, the unit passes a lot of room air over that water, so room 
deodorants, cooking fumes and oils, insecticides, paint, smog and all 
other household air pollutants can add to the "stuff" in solution. I 
wouldn't drink it, and I certainly would only use it for fish in a dire 
emergency. [That is, it's better than being dry!]

Unless hardness is a big problem, running tap water through a simple 
carbon filter is probably safer and more likely to provide healthy 
water for the fish. Hardness must be dealt with by RO or deionizing 
units. The half-way deionizers called "water softeners" are not much 
use for this purpose, for they still leave all the sulfates, 
carbonates, etc. right there in the water.



Wright Huntley (408) 248-5905 Santa Clara, CA USA

Humidifier, was Re: New Fish Room

by plasticolor/
Date: Thu, 12 Nov 1998
To: apisto/

>> Dehumidifier water is iffy.  THese units usually have copper or aluminum
>> condensation coils that may contaminate the condensed moisture.

The dehumidifier is now an expensive door stop.

I agree.  There are cheaper ways of obtaining soft water (and cheaper
doorstops).  I´ve never tested dehumidifier water for metals, but I
understand that tannic acid in the tanks (leaching from bogwood and oak
leaves) forms insoluble precipitates with metal salts. Tannic acid was
(is?) even used as antidote against heavy metal intoxications.  I use water
from the dehumidifier at home (4 gl./day) and haven´t had problems so far.


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