I have used fertilizer sticks in my 150 gallon plant tank with some
success. My reason for using them is that they were cheaper than the
aquarium products. Although the plants seemed to love them, I started
having a problem with algae. Over time, a green slime appeared that
eventually killed all my plants. Mike T. in Newark De. told me in no
uncertin terms that my use of terresterial fertilizers was the cause of
my problem. Simply too much nitrogen!!
I no longer use them, and prefer to use his plant tablets, water changes,
and a little "dirty" water from another inhabited tank.