EI and Micro ferts

[keymaker]

Tom, I was just looking at my excel calculator (posted on UKAPS) and realized, that the range top for the Fe was misspelled. It was 5ppm instead of the 0.5 ppm you suggested.

You specified the EI range for Fe in your description like this: "Fe 0.2-0.5ppm or higher (?) "

Could you explain in more detail what you meant by this - especially the question mark at the end. Does that mean you are not entirely sure that the top of the range is 0.5? Why?

With my current Micro dosing there is 0,8-1,4 ppm Fe in the tank. What do you think, have you experimented with these levels before?

It would be really useful to know the other Micro components' EI range too...

 

[keymaker]

Any thoughts on this?

 

[Tom Barr]

I honestly do not have an upper bound for Fe.
Research suggest about 6ppm is the max growth rates for Hydrilla using Fe.
8ppm or so causes a reduction.

6ppm is extremely high.

I add a lot and then back off slowly and watch each dosing volume per tank for a few weeks, typically 3. When I see a negative response, I bump the dosing back up to the next highest level.

This avoids any test kit.

Some suggest a specific amount of Fe added daily or a residual, this is a bad method really. There are many reasons why that's a bad issues and I spent considerable time many years on this one issue with some really smart people.

For hobbyists, the above method is likely the best solution, for researchers, we can measure it in terms of uptake in the plant tissues as well as overall growth rates over a range of ppm's dosings. KH also influences and the type of chelator as well, so things get weird real quick.


Also, Hydrilla might not be a model plant for growth on Fe on average, and factors like CO2, light intensity, NO3, PO4, fish load, food type etc, all play a huge role, whereas Fe is really pretty far down on the list............So all those other factors need addressed and kept independent before you can say much about Fe.

That's tough to do.

So I leave the upper bound as questionable, we added .7ppm to 1.2 ppm for many years using TMG, which was a lot and cost a lot, so the main trade off was cost for using less vs more.

If the cost is not an issue, adding more dose no harm, whether it helps, I'm not sure.

I simply do not know due to experimental issues and the fact less is known about CO2, than Fe. No one has killed fish with Fe, nor does it cause algae, CO2?
I'll go after the issues I can answer and that are more important.

I added a lot of SeaChem floiurish to test the toxicity with shrimp and fish, about 200mls per 20 gal of tank. No issues of any sort, the tank was amber colored tea colored for 2 weeks, but no harm came to fish or plants............

So there's no toxic issues, nor algae inducement.
Just waste mostly near as I can tell.
Using TMG, the above seems to satisfy most planted tanks(0.2- 0.5ppm modeled estimated dosing (not actual residuals in the tank).



Regards,
Tom Barr

 

[keymaker]

Tom, thank you so much for your detailed answer!

The HEEDTA chelator that we use in our micro ferts should be stable enough in our hard-water (KH 9, GH 20) environment. Plus I dose daily as you suggested before. Having 1.4ppm Fe in our test tanks (3 tanks so far) in the past 3 weeks has not produced any negative reactions so far, so I can verify your hard-water dosing experience with Fe. We did 80% water changes on a nano twice-a-week, the others went with 50% weekly. All around 4 WPG lighting.

The cost is not an issue, so we will keep doing that in the future.

Thanks again.