The metallic (e.g., cuprous oxide/cuprous thiocyanate) or non-metallic (e.g., Econea®/tralopyril) biocides in antifouling bottom paints that effectively prevent hard fouling growth like barnacles and zebra mussels do not combat soft fouling growth like slime, algae, weeds, and grasses.
To repel slime and algae, the bottom paint must contain either Irgarol® or zinc pyrithione (generic name for Zinc Omadine®), which is the same ingredient used in anti-dandruff shampoos.
Antifouling bottom paints that help prevent that 'green beard' at the waterline include Interlux Pacifica Plus, Interlux Micron Extra, Interlux Micron CF, Pettit Hydrocoat SR, Pettit Vivid, TotalBoat Krypton, and ePaint Ecominder antifouling paint.