We will identify each type of freshwater algae and then learn how to eliminate them. However, you should know that on a newly installed tank it is normal to have algae, do not worry, everything will return to order without your intervention.
On the other hand, in a normally broken-in tank, the proliferation of algae always comes from a deficiency, from unsuitable lighting or from the parameters and quality of your water. An explosion of algae is a sign of a significant imbalance.

Algae benefit from an excess of nitrates (No3) or phosphates (PHo4) or from the lack of a trace element that paralyzes the growth of plants. A poorly maintained filter accelerates the growth of algae by leaving nutrients in the water that benefit them. Filters produce nitrates and too much nitrates grow algae! it is therefore necessary to wash and maintain its filters carefully.
There are 2 main groups of algae: Macro-algae which are fixed in a thallus (organized like a plant) and phytoplankton, which floats in open water (clouds the water).

To limit or avoid the invasion of algae when starting a new aquarium

You are advised to:
- plant as many fast-growing plants as possible (see list in section "plants for our loulous") to create competition, (even if it means removing some within 6 months when the balance begins to improve and replace them small little by little by other plants which grow less quickly but which will be larger or more decorative; Anubias, Echinodorus)

- do not light all the neon or led tubes at once for 12 hours ....
but only connect 2/3 of the lighting for about 10 hours then gradually increase over 2-3 months.
To limit the presence of algae, you must
- good lighting, 1 Watt for 2 liters of water. In lumens: ideally 30 lumens per liter) for 11 to 12 hours and in one go. (No cut, the plants do not really appreciate. For our axolotls we can clearly reduce this number of lumens of course but you have to choose the suitable plants (see plants section) which will be fast-growing plants, which allows them to compete with algae;
- LEDs with a temperature (see lighting section) of 6000 to 7000 K or neon tubes changed every 10 to 12 months. After this time, they still light, but their spectrum has changed and it is the algae that benefit.
- levels of Nitrates and Phosphates kept low: The major effect of nitrates is to boost the growth of algae, since these are their basic nutrients.
- a well-monitored iron level. Too much iron encourages algae and not plants.
In general, an iron level of 0.05 to 0.1 mg / l is recommended.

Bad advice
Avoid using anti-algae products, which upset the balance of the aquarium and create other problems. Anti-algae also act on plants by growth inhibitors, they do not only block the growth of algae ... but they also stop the growth of plants which again promotes the growth of algae and therefore the remedy is worse than evil!
It is sometimes recommended to cut the lighting for 4-5 hours in the middle of the day! This affects the algae, but especially the higher plants that are the plants.

We manage to limit algae by respecting basic rules
- regular water changes 30% per month. Overpopulation = pollution.
- lots of plants, and give preference to fast growing plants.
- no overfeeding.
- regular monitoring of nitrates and phosphates.
It is useless and harmful to aim for a rate of zero No3 nor zero Po4, a little Nitrates and Phosphates are necessary.
Ideally, a rate of 15-20 mg / L of NO3 and a rate of 1 mg / L of Po4 prevents algae growth and promotes plant growth!
In the event of a lack of No3, it is recommended to space out the water changes or even to slightly pollute the tank, for example by increasing the distribution of food to increase the nitrogen load a little. We can also simply add Nitrate of potassium, (KNO3). Clean the new plants well to avoid incorporating algae in your aquarium, adding a few drops of bleach but never more than a minute in this mixture.