[APD] Re: N and Echinordorus in the roots

[Thomas Barr <tcbiii at earthlink_net>]

Jim,

I have grown all those species so darn large, I refer to them as "trees".
You need to account for the other factors before concluding Echinodorus species require or otherwise need substrate N.

I've never had any issues with their long term growth other than they get too large for most any tank except 180 gal plus tanks.

Some of the smaller types does well in tanks, the larger ones? Forget it.

This experience is some 15+ years of not using N in the substrate and the water column(I used RFUG's and these did amazingly well, too well).

I've added N to a control plant, eg one with adequate supply of nutrients in the water column have found NO CHANGE in growth rates/health etc using a substrate macro source(or any other plant for that matter).

Fe is the only element that showed some benefit when in the substrate. 

So if N is requitred for good growth and your test at 50ppm NO3 showed issues, why do my plants do so well, err too well, when the NO3 is less much less than 50ppm? 

Something else was causing the problem.... not N or a macro substrate source.
If you limit the water column, then the plant will go after the substrate sources. 
Swords, Crypts do not prefer root uptake as so many seem to say all over the web. 
They do amazingly well with water column dosing only. 
I know this very well as I've had boith genera for a very long time using RFUG's with plain old dirty sand.

If you have poor habits, then substrate ferts will help maintain a more stable system, but it's due to leaf vs root uptake.

You need some control(the RFUG are very good for this) and to account for the other parameters(CO2/Fe, PO4, K GH etc) before you can make this deterimination.

Regards, 
Tom Barr





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