In practically every aquarium, small green, punctiform algae develop over time on the aquarium panes. They are quite stuck and can only be scraped off with razor blades or other objects. These algae are a form of green algae that are completely harmless. Their occurrence even indicates quite good water conditions. Only when they appear in heaps on plant leaves can they damage the plants by shading the leaves.
Another type of punctate algae is the black punctate algae. It is easily identified by color and typically occurs on older leaves of relatively slow-growing plants such as java fern. When heavily infested, the leaves look as if they have been sprinkled with coal dust. Less black spot algae can be found on shaded leaves than on brightly lit leaves.
Causes of spot algae
Both types of spot algae develop with good lighting and an excess of nutrients. If the occurrence is small, there is no cause for concern and countermeasures can be dispensed with. An algae-free aquarium cannot be achieved. A certain amount of algae is even welcome as an additive to the diet of fish, snails and other creatures.
Countermeasures to spot algae
Planting the aquarium with as many different and fast-growing plants as possible offers a certain degree of protection against spot algae. Ideally, these consume the available nutrients so that no food is left for the growth of the algae. Nutrient input and lighting must be precisely adapted to the needs of the plants. However, it is hardly possible to create a completely algae-free aquarium in the long term, as this would require constant and perfect balance. This cannot be achieved due to the constantly changing conditions in the aquarium.
If the spot algae grow too much and too quickly, fertilization should be reduced or even stopped altogether. The iron content should be adjusted to a value of around 0.1 mg per liter of water. Another measure that should be considered is a reduction in the illuminance or the duration of the lighting. Some snails, e.g. B. ramshorn snails, in the aquarium help to keep the infestation with spot algae within limits. However, care must be taken not to feed too much, otherwise the snails would rather eat food than algae.
distance
Spot algae are quite difficult to remove. Heavily infested plant leaves are cut off. The windows are scraped off with window cleaners that are specially available in stores or with «replacement products» that are available in the household. A whole range of suitable devices are listed with advantages and disadvantages in the tips and tricks.