water conditioners and iron
> From: "A. Inniss" <andrewi at u_washington.edu>
> Date: Mon, 23 Dec 1996 02:35:38 -0800 (PST)
> Subject: Water conditioners & Iron
> It just recently occured to me that my water conditioner is most
> likely affecting the iron levels in my tank, since it claims to "detoxify
> heavy metals."
> Now, it is my understanding that it does so by chelating them.
> This point leads me to a few questions:
> 1). Is the iron I add not making it to my plants? If the water
> conditioner is merely chelating the heavy metals(including, presumably, iron),
> then is the iron made forever unavailable,or is the iron now in effect double
> chelated? (I use Flourish, whose iron is already chelated). If the iron
> is simply "double chelated," then I presume it would eventually be
I don't quite know what you mean by double chelated, although it sounds
like it belongs in a SeaChem ad. ;)
I would assume that Leo is using EDTA to chelate the iron in flourish.
It is probably stronger than the thiosulfate in the water conditioner you
> 2). If it turns out that this particular water conditioner _is_
> going to make iron unavailable, what water conditioners (if any), do the
> rest of you use?
I doubt that thiosulfate is a long-term problem with iron. Indeed, I am
skeptical as to how effective it is in tying up any heavy metal for the
long-term in the aquarium. Metal salts precipitated by thiosulfate
should be liberated when the thiosulfate is oxidized.
> 3). As a related question, what does happen to the excess
> chemicals from water conditioners if they are not all used up doing their
> job of eliminating chlorine etc.? Can some of them continue to build up
> in the aquarium, since they have nothing to bind with, or do they
> dissipate, react with other chemicals in the aquarium, or do something
Thiosulfate reacts with dissolved oxygen in the water. Terminal reaction
products are, I believe, sulfur and sulfate ions.
> 4). The listed ingredients of the water conditioner are:
> K CO3,
Probably KHCO3, potassium bicarbonate
got me. Could be either something with a carboxylate and an alcohol or a
carboxylate and an aldehyde. If the latter, then it is probably used to
react with ammonia and be a dechloraminator in conjunction with the
EDTA, a chelating agent.
A surfactant. I see no reason for its inclusion.
I'm guessing that this is in polymeric form. Probably starts as a
benzene derivitized with an aldehyde and amino group, which should
spontaneously couple to form a high polymer, fairly hydrophillic, but my
guess is that the tween is present to disperse it.
> I don't recognize some of these, and with the many isomers possible, don't
> even know where to begin tracking them down. (George, think you could
> pester your wife with this ;-)? ). Others I suspect are listed
> inaccurately:e.g. that should be K2CO3, not K CO3, shouldn't it?
I guess my question is, why are you using this water conditioner? What
do you think it is doing for you that a few drops of sodium thiosulfate
would not do?