What kind of plants? I use a small oral syringe for baby medicine from any common drug store. I just take the normal dosage for the size of tank and squirt it directly on affected area. You might want to check water circulation though, once I added/changed water flow I dont have as bad of an algae problem.Does anyone have any experience with excel spot treatment? I think I have some clado on my glass and on some plants. Im afraid that the excel will kill plants.