While healthy plant mass is the #1 natural defense against algae, life is often unpredictable.
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.

“APT Fix does not harm healthy fish, shrimp and other livestock within its recommended dosage. Of course, if you keep very sensitive livestock, you should avoid all products that give you any concern.”