Potts, I would talk to someone knowledgeable about the amount of fertilizer to add. It might be different in Canada than here in Texas. Overfertilization can be lethal to your fish but highly appreciated by noxious vegetation. Be careful. Another point: The fertilizer is heavier than water. Make sure that you mist it onto the water instead of dumping or spraying. I've seen a lot of recommendations about how to add fertilizer but this method has worked well for me. Just remember that it is better to slightly underfertilize than to overdo it.