kekon

Some time ago i purchased some specimens of this plant and put it into my tank. Unfortunately it didn't grow at all. I watched it dying day by day. It lost its rich red color, the tips got dwarfed. Being aware of too high NO3 levels and too low K that cause stunting i dosed little NO3 and much K. Also, Ca and Mg were under control. It was all in vein, the plant looked ugly. Because i use only RO water i know what amounts of nutrients are added into the tank. The micro fert i used had the same amount of boron and zinc. I decided to double boron content and started to dose. (now, it's 0.008 ppm Zn and 0.015 ppm B weekly)
Within a week Macrandra "woke up" and started to grow ! Now it grows very fast and have rich red colors. Then i set boron and zinc dose to 1:1 ration. The plant still grew but not as fast as before. I set B:Zn to 2:1 again and the plant began to grow fast again. So, it seems that the cause of bad healh of this plant was too little boron. However, one has to be very careful when adding more boron - this nutrient is very easy to overdose and become toxic to other plants !

BryceM

Kekon,

It's good to see you. R. macranda is certainly a demanding plant. Your observations about boron are interesting. Most of us in the hobby just assume that our particular micro mix will supply the correct amount of all of the traces. It's probably good to be reminded that not all assumptions are always accurate.

Bert H

Great observation, Kekon. Do you add this via boric acid?

kekon

Yes, i use only boric acid as a source of boron. When i was watching different tap-water contents reports i found there were different concentrations of boron - from 0.008 ppm to 0.1 ppm.

Avalon

Interesting observation. I'm a little hesitant to say it's Boron since there are so many other factors that it could be. I keep this plant in RO water and find it very easy to grow. My only source of B & Zn is Tropica's Plant Nutrition Liquid. Interestingly, it has exactly a 2:1 (B:Zn) ratio. Hmmm...

BryceM

I grow it under MH lighting in reconstituted RO water with Tropica's micros too. Same result as Avalon - it grows pretty well. At times, it even becomes a nuisance.

suaojan

My experience with Rotala Macrandra is that it needs a large amount of light and CO2. In good conditions, you'll see lots of pearls under the leaves of R. Macrandra.

HeyPK

Of all the micronutrients, except possibly iron, boron deficiency has occurred the most frequently for me. I have seen it when I was in Massachusetts, Wisconsin, and, now, central Mississippi. Boron deficiency is always a possibility when one gets stunted tips and/or roots. Calcium and iron should also be considered. I don't think I have ever seen zinc deficiency. Perhaps my regular micronutrient dose takes care of zinc needs.

Bert H

Kekon, with the toxicity of Boron being what it is, exactly how much would you add to a given volume of water? How much of a margin of error is there with this element?

This topic has come up in the past. A while ago I bought a bottle of boric acid, but never did use it, so I am curious. Thanks.

HeyPK

Burt, What is the concentration of the boric acid? I made up some 0.1molar boric acid (6.2g/L) and I add 1 ml of that per gallon of tank water. This cures boron deficiency for a very long time, and I have not seen any toxicity symptoms.