Re: Iron levels

[Thomas Barr <tcbiii at earthlink_net>]

> 
> Karl Schoeler's label says to adjust the N.G. dosage to bring the iron to
> 0.5-0.75 ppm. Given that SeaChem is a serious company, and that Flourish
> and Flourish Iron are about the same price, what is the rationale for a
> separate, iron-only product like Flourish Iron, other than one might dose
> some other ingredient in reg. Flourish too high if monitoring iron alone? I
> ask this given that some of us are dosing some products at at least 3 times
> the label dosage and *most of us don't test for much other than iron*. Is
> there a chance of putting our fish at risk, or of causing plant uptake
> problems with an improper trace-element balance? I know we've discussed
> iron levels and each of us can monitor iron levels, plant growth and algae.
> But I'm wondering about trace-element balance vs. iron dosing."

I've used levels as high as 2ppm in my tanks based on a 90$ Hach test kit.
I'm much more inclined to use the higher numbers.

I really think testing for this iron as proxy for all the other traces is
the wrong way to go about it.

First off they are traces.......they are critical, but not much is needed.
Second off iron does some funny things in water. What are you testing?
I don't know, is it bioavailable iron? Will plants remove 0.2ppm a day? I
think it's EXTREMELY difficult say much about that part which is a key if
you wish to discuss a tested level. It also is an issue of the test kits
themselves which are variable if you compare and make your own standards to
verify the kits against.

A more indirect method seems a much better rule of thumb for dosing traces
and or/iron alone.

This involves 2 set ups.
1#
One of these method involves no iron in the substrate and the other involves
various sources of iron in the substrate.
The next part involves dosing of the water column as the dependent variable
since there are no test kits for testing the substrate's iron content or
anything in the substrate for that matter.

In order to say anything about the dependant variable, in this case iron and
traces in general, we MUST keep the OTHER factors influencing plant growth
stable during this period. If not, the test must be repeated over again.

While quantitative data would be nice and it is possible to do, it's very
difficult for a home aquarist to do. A more qualitative method relies on
your own eyes and plant health over about 3-4 week's time.

To do this method you need to have the PO4, K, NO3, CO2 and lighting in a
good stable optimal range during the testing period.

Fair enough. This exercise will get your plants and tank going very very
well ANYWAY. So you have nothing to lose as far as tank success.

That's a win-win deal.

So rather than approaching this from a test kit or some number, approach it
from a known standards approach.
I do this all the time with folks all over the world for most all nutrients.

You know the concentration of the trace mix. You know the volume of the
container(aquarium) correct? So adding X amount of salt into a container of
X size will yield a new diluted concentration.

No test kit is needed since you know the volume and the concentration you
started with. Adding a 1 liter volume of a 1M salt solution to 1 liter of DI
water will give you 2L of .5M salt solution etc.

So that will give you the actual amount of Trace you are adding.

Now what do the plants actually use here? That's another question and only
the plants can really answer that. Some folks might need to add only tiny
amount of traces or else they get algae. Sure that's true for them and
there's also a good reason for this, they plants are not supplied with the
other nutrients they need, like PO4 or NO3 or enough CO2 etc. An already
touchy set up is easy to tip to the algae's side.

Addressing the macro's adequately will greatly reduce this effect.

They blame the traces for their algae problems. If the other variables are
in good shape, adding large amounts of traces should have a good effect on
plants and less on the algae.

I've have shown this to be the case dozens of times and well.......
everyday.

The how:
The method for figuring out how much is simple. Keep the other nutrients in
good shape. Next add 1 ml per 20 gallons or some ratio thereof. I started
high and then worked my way down. Most folks are scaredy cats so they start
on the low side.  
Add this amount every 2-3 days for 3-4 weeks. Then add 2 mls/20gallon for
3-4 weeks. Then add 3, 4 up to about 5 mls/20 gal 3x a week or so.
I've added 10mls/20 gallon for 4 weeks. But the plants do not respond any
better on that routine verses 5mls/20 gal 3x a week with a flourite
substrate.
They did respond a bit better when NOT using a flourite substrate or a non
iron rich substrate.

This gets around testing completely. It's amount and frequency based. It
gauges the plant's needs directly though observations.
 
For more/less lighting, reduce __the frequency__ but not the dosage.
Example: add 5mls/20gallons 1x a week for less than 2watts/gal, 2x a week
for 2-3watts/gal and 3x a week for 3-6watts/gal.
The same approach can be applied to NO3, PO4, K etc.

 This is for continuous dosings and also requires weekly 50% water changes
or else lots of testing:)

I'll take the water changes which I know what I'm, adding and not rely on
the test kits so much. It's good to test, but it's also a good deal of work.
Good test kits are expensive and might not tell you what you need to know in
the first place (bio available iron).

Regards, 
Tom Barr