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Re: Aquatic Plants Digest V2 #1101
Subject: Re: Water conditioners and chloramine
Don Hutton wrote:
>I read an article in AFM about a planted discus tank where the author
>states he doesn't worry about the chloramine in his water changes because
the plants
>use the ammonia and the pH is low. The magazine editor added that this
was not
>recommended practice.
Ahh... Misquoting (or in this case mis-paraphrasing) is rampant these
days.<g> I just happen to have the article in front of me. "Discus are
Just Fish" by David Lass, Aug. 1997 AFM. (I assume that this is the one
you are referring to)
Not my article, but written by a good friend of mine. I did the photos and
diagram, the water testing (as David is definitely not big on testing) and
the initial editing of the article, and argued back and forth with Ed about
the wording of the editor's note.<g>
Here's what the article actually says:
"... The fluidized bed filter was added when my town changed from using
chlorine in the tap water to chloramine. The increased biological
filtration was necessary to process the excess ammonia as the chloramine
breaks down.
Approximately 25% of the water is changes weekly, and is replaced with cold
water, straight from the tap with no conditioning at all."
Ed adds:
"(Readers are advised not to use this method for water changes unless you
are able to determine that the amount of chlorine or chloramine in the tank
will be so low that neither the fish nor the nitrifying bacteria in the
biolological filter will be adversely affected. Chlorine and chloramine
levels in tap water can vary significantly from season to season, and may
be at far higher levels during certain months of the year. The chemicals
for removing chlorine and chloramine are inexpensive and easy to use,
whereas replacing your fish will be far more difficult and expensive. - Ed.)"
David goes on to write:
"The pH of the tank water is 7.2, carbonate hardness is 2KH, general
hardness is 4GH, nitrate is 25 mg/L and phosphate is 0.5 mg/L. Those of
you who are familiar with planted tanks, and especially discus tanks, may
notice the unusually high ratio of nitrate to phosphate. The rather high
nitrate reading is the end result of the breakdown and biological
processing of the ammonia portion of the cloramine into nitrite and then
nitrate (the chlorine portion was already handled by the granular activated
carbon in the filter)."
While it is true that plants use ammonium, whether they can use all that is
produced by the reduction of chloramine is very dependent on how much total
ammonium is available to them and how much they need at the time. David
found that his plants were _not_ using all the ammonium produced, and
installed the fluidized bed filter to handle the excess. I suspect another
approach that could have worked was to increase the light level to the
point that the plants had an increased need for nitrogen.
>Does activated carbon remove chloramine? If so, why doesn't it remove
>ammonia from aquaria?
Activated carbon will remove chlorine, not ammonia. It is necessary to
break the chlorine/ammonia bond, and deal with both substances. David has
found an approach that works for him, but I think that Ed is right. For
most people, commercially available chloramine removers are safer, and a
cheap and effective solution.
Karen Randall
Aquatic Gardeners Association