This is an effective approach for removing algae on hardscape: wood and rocks. Avoid this method for plants.
This is our usual approach to treat algae on plants. To increase effectiveness, pause the filter during spot-dosing (just a minute or however long it takes you to spot-dose:) And don't forget to turn the filter back on!
If you have alot of areas to cover, you can exceed the 1ml per 10L limit. Spot-dose on affected areas, and perform a 50% water change after spot-dosing.