I went on a vacation for about 3 Days, and asked my parents to feed my fish while i was gone. When I got back my tank was almost covered in black beard algae. I had some already, but it was in small amounts. I fear that my parents overfed my tank, and there was alot more nutrients in the tank. This is kind of reinforced since several of my plants grew by alot, namely my Water sprite, Dwarf Sag, and ludwigia. All of my Anubias plants are also shooting out extra leaves.
I would like some tips to draw down the amount of Black Beard algae in the tank, I'm planning on doing a massive water change to take out excess nutrients, and probably cutting down my light, but i've heard BB algae can be pretty resilient, so i'm not sure about doing a Black-out.
1. Start dosing excel daily. When you are about to dose it, turn off your filter and powerhead. Use a medicine dropper and apply excel directly to the affected area, then leave it on there for 20 minutes before turning your filter back on. You should eventually see your BBA "pearling", followed by turning white and falling off. Alternatively, you can also manually clip off affected leaves if you wish.
2. Reduce your lighting duration and add a "lights out" period in between. For example, reduce you lighting from 12 hours a day to 8 hours, and out of that 8 hours schedule a 4 hours lights off period in between. So you will do: 4 hours on, 4 hours off, then 4 hours on again.
3. Reduce feeding frequency. If you feed your fish twice a day, feed them once a day instead now to avoid excess nutrient building up.
4. Get algae eating critters. If you have a large enough tank (40 gallon+) you can get a siamese algae eater, they are known to eat BBA when they are young. Careful not to get a falseSAE though. If you have a smaller tank, stock up on enough amano shrimp. Do not feed your amano shrimp. If you keep them hungry enough, they will start munching on BBA as well. You will need at least 1 shrimp per gallon to do the job if your BBA outbreak is bad.
5. If you are dosing liquid fertilizers, stop. Begin dosing root tabs instead since BBA draws nutrients directly from water. This will prevent BBA from utilize the nutrients in the water while your rooted plants can directly absorb them from their roots.
6. Get more fast growing plants to outcompete BBA for the available nutrients. Giant duckweeds, water sprite, water wisteria, anacharis, pennywort, ludwigia, java moss are all pretty good candidates.
7. If you dose CO2, keep it at a constant level above 30 ppm. (Even during lights off) Fluctuation of CO2 levels are known as a trigger to cause BBA outbreaks (which is often the case with DIY CO2).
Good luck! I am currently battling with BBA as well, and it has been a constant struggle. Feel free to ask me if you have any other questions.