Re: Dupla iron supplementation: a query

> From: "Denney, Richard" <rdenney at MSPO1_MED.UTMB.EDU>
> Date: Mon, 25 Nov 1996 11:51:00 -0600
> Unless I am mistaken, Dupla drops, with their 1180 ppm iron
> (information from George Booth), are added in such small volume that
> they contribute very little to the total iron concentration in the
> tank.

I guess your math is right so I would agree with your conclusion.
However, the drops are only used to *replenish* the iron and trace
elements that are used by the plants or oxidized over the course of a

> But I do not understand the rationale for adding iron in both the
> tablets (with water changes) and daily drops. If the plants need the
> drops for the extremely small amount of iron they contribute, what is
> the purpose of the iron in the tablets?

The tablets add enough iron to make up for the large reduction seen
during a water change.  The drops replenish the iron used or lost over
the period of a day. 

However, this doesn't really explain why a level of 0.1 mg/l of iron
is "right".  If plants are only using 0.0007 mg/l per day, why is a
level much greater than that required? 
> Laterite is the other, principal iron source. Does anyone know how
> much of the iron in laterite escapes to the water column?

In a freshly set up tank, the level of iron in the water is around 0.5
ppm and decreses steadily. I don't know if this is from the laterite
or from the initial big dose of DuplaPlant tabs. I don't think much
leaches out of the substrate.
> Any data on iron concentrations in aquarium water with laterite which
> has not received another source of iron?

Not that I've seen.  

BTW, think one word:  www.dupla.com

Maybe they know.  Maybe they would tell you.  Maybe not.