Big Tank$ mean big buck$!! Blyxa japonica is a great plant, but if it grows at all well you won't be able to get by with pruning it once every two months. When it grew for me I had to be involved with it about once a week. Unlike typical stem plants it generates new plants alongside the original one, and as they start getting crowded, the new ones just grow suspended in the water. When I would thin it out I usually reused only about 20%, if that much, of what I removed. But, it is such a beautiful plant!