What to do in case of brush algae?
I have had black brush algae for a while. I have already replaced all plants, adjusted the lighting time and used a peat based additive. What else can I do?
the following approach is effective in the long run: Regulate the ratio betwen nitrate and phosphate in a way that the plants are just sufficiently provided with nitrogen and phosphorus, but nothing is left over for the algae. This often means to reduce these nutrients. Especially in case of beard and brush algae (which biologically belong to the red algae, even if they do not look red), it is important to control the phosphate level as well as the iron level if it is too high.
You can achieve nutrient reduction by
* reducing the number of fish and the food amount
* abundantly adding fast growing plants
* generous partial water changes with water low in nitrate and phosphate (!)
* possibly using a denitrifying slow flux filter
* especially in case of brush algae: Using sera phosvec Granulat in the filter
* not using care products that contain nitrate and phosphate
* creating optimal growth conditions for plants (good lighting, possibly CO2 fertilization, suitable bottom ground, etc.)
Some patience is required, it may take several weeks before there is a visible effect.
Dr. Bodo Schnell