Removing green deposits

All information about the removal of green deposits, algae and mosses
Effectively remove algae
Remove the green deposit
The solution: ALGEN REMOVER
Improved aesthetic appearance

Cause and prevention

Green deposits can occur on surfaces that remain moist for long periods of time. Another important factor is a lack of direct sunlight. A lack of sunlight prevents moisture in the surface from evaporating and allows green deposits to form easily. Green deposits can occur on almost any surface. Common surfaces include tiles, bricks, wood (garden fencing), concrete tiles, natural stone and roof tiles. Various soft substrates such as convertible car roofs, sun screens and parasols are also vulnerable to green deposits. Effective removal of green deposits with MAVRO products.

It is not unexpected that green deposits often form during winter time. In these periods the sun is low in the sky, and the power of the sun is at its lowest.

What are green deposits, and how do they form? Green deposits are a collection of algea and moss (lichens). The deposits owe their green colour to the chlorophyl that these organisms use to sustain themselves. Just like other plants and trees, algea and moss provide themselves with vital oxygen trough photosynthesis.

Want to know more about algea and moss?

Properties and effect

Green deposits are unwanted in most situations. They give a neglected and untended appearance to, for example, a driveway, garden or the side of a house.

Besides damaging the appearance, algea and moss growth can damage the surfaces they live on. Algea and moss are able to retain moisture and will keep growing undisturbed. In the long-term this will make damage the surface, making it more porous. A porous surface is able to hold even more moisture and create an even more ideal situation for new growth. Left untreated, algea and moss growth is able to damage a surface beyond repair.

Algea and moss in gardens, on wood, tiles or balconies will cause a serious slip- and fall risk during rainy periods.

Want to know more about how algea and moss damages a surface?

Cure and prevent

It is essential that green deposits are stopped at the source. As we know, green deposits start with algea growth. Removing these algea will prevent moss to grow, preventing daamage to the surface. Once mosses have started to grow, removing the underlying algea is difficult.

There are various methods for removing green deposits/algea. Not every method is effective, and some can even cause more problems in the long-term.

Two common do-it-yourself algea removers are made using soda and water or ammonia and water. These mixtures may be easy and cheap, but they are not very effective.

Green deposits can also be removed using high-pressure water. Removing algea and moss using high pressure may seem very effective, but will make the underlying surface rough and porous. Making it an even more ideal surface for algea, causing them to come back faster, and stronger.

Lastly there are professional algea removers. These chemical mixtures are often based on didecyldimethylamonniumchloride (a quaternary ammonium salt) and surfactants. MAVRO ALGEN REMOVER is an example of a professional algea remover. This (and related) products will effectively remover algea and leave an invisible residue that protects the surface from new algea growth.

Even after using a professional algea remover such a ALGEN REMOVER, green deposits will come back after a while. Luckily there is a way to prevent algea growth completely. An excellent method for preventing algea growth is by making the surface hydrofobic. This is done using an impregnating/hydrofobing agent such as MAVROSEAL WB or FLOORGUARD (for floors and walls respectively). Treating surfaces with these products will make them fully water-proof for >5 years. A hydrofobic surface will therefore remain dry, even during cold and wet seasons. Algea and moss will not be able to grow and your surfaces will remain clean.

Interested in impregnating/hydrofobing your surfaces?


Chemical algea removers such as ALGEN REMOVER are biocides with a specific end-goal and (regulated) guidelines.

The product is required to have a CTGB (College Toelating Gewasbeschermingsmiddelen en Bactericiden) registration number. Additionally, because the product contains surfactants it must adhere to regulations described in the dutch “tensidenbesluit EG 648/2004”.


Remove any loose material and contamination from the surface such as leaves and sand. ALGEN REMOVER may only be used in dry conditions. Dilute ALGEN REMOVER 1:10 to 1:40 depending on the degree of contamination. Apply the diluted product using a low-pressure sprayer. Let the product dwell on the surface for 24-48 hours. The process is accelerated by direct sunlight. Rinsing with water is not neccesary, as the product will leave a protective residue against new growth.

Legal instructions

Only allowed to use as an agent against green algae. This product is not allowed to treat hard surfaces and equipment along watercourses in combating green deposit of algae. This agent is toxic for fish and other aquatic organisms. Prevent that the liquid reaches the surface water


Wear suitable protective gloves, cloths, googles and face protection. This product is corrosive for the skin and eyes. For more information consult the safety data sheet.