Quite possibly yes. Maybe not a case of green water (if thats what you mean by bloom) but more likely excessive hair, beard, staghorn, etc.The Sears Conlin recipe is unfortunately a "one size fits all" solution to dosing ferts. I dont think most people use this recipe because it really should be finely tuned for the specific aquarium. Many (myself included) dose each fert dry. This way you can dose only what you know (by using test kits) your tank is using up. I dont recall how much KNO3 is in the recipe, but I would suspect that it may be more than you need considering feeding and po4 already in your water supply.