The 2HR Aquarist APT Fix Algae Treatment 200ml

The filter or CO2 diffuser gets clogged. Grandpa overfeeds the fish. The auto-timer takes an unannounced holiday.

These shocks ( seemingly insignificant to us) weaken plants and give algae a window of opportunity to spawn.
APT Fix works to rebalance the system by targeting the fundamental weakness of algae- their comparatively less developed protective cell walls. When spot-dosed per the recommended dosage, it instantly arrests algae growth while allowing plants to recover.