I aggressively treated my plants for black brush algae. I did two sessions of draining the tank to about 20% water/80% empty, then spraying the leaves with hydrogen peroxide. I trimmed the leaves I missed after the second treatment. My plants now look a little thin and melted. I also treated with root tabs and normally liquid fertilizer after water change. I do have co2 on my my tank but I usually go easy on it because I gassed many fish. anything else to help plants recover.