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 !
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 !