Hi, sorrie to all I replied so late.
Anyway, the lotus grows too fast, sometimes too soon. I keep pruning them back. Then they grow slowly and after a particular 'threshold', they start to sprout very quickly. Then the cycle goes again.
I found that they grow well when I inserted this root tab into the substrate. I don't really have any problem for my ltus except sometimes they develop holes (a sign that nitrate levels may be high).
Oh yes, they need VERY strong light. As U can see from my tank, the light is illuminated at least at 21W, which means about 4W per gallon. Seems that they thrive under such conditions. Before I upgraded to this strong lighting, the lotus was just growing so-so, it looked rusty red. After I add in the extra lighting and the pressurised CO2, they now become quite bright red.