i recently bought one of those special windelov java ferns, i have anchored it to one of those texas holey rocks in my 29 gallon aquarium with one 20w flourescent bulb. Ive read that java ferns dont need that much light so i havent seen my lighting as a problem. ( i have no other plants in the tank). My problem is that i have noticed that some of the leaves have been turning brown.....what am i doing wrong????? Thanks in advance