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Algae (black or Green), Mildew, Mold, Moss
     Growth In Showers, Patios, Walls, Etc.

This growth requires three factors.

  1. Spores in the air
  2. Constant moisture
  3. A surface that allows for "rooting"
You cannot do much about the spores, but you can make a difference to the constant moisture and the surface characteristics.

An absorbent surface accumulates moisture that exists during the time that the water source is not operating (rain, sprinklers, showers, etc.). The next occasion of water source happens before the surface has dried out. Therefore, the moisture is constant even though the source has temporarily stopped.

By stopping water absorption you stop the continual presence of water, therefore you break the cycle of growth. You stop water absorption with the appropriate sealer.

You revise the surface characteristics that allow "rooting" with the correct sealer.

Various cleaning product suggestions to remove mold, algea, mildew, moss:

  • For powerful cleaning that is not a concern for any surface type:

  • For cleaning showers and spas with heavy buildup that could be considered "restoration" and require a more aggressive approach, see
For prevention, seal the surfaces. See the "Surface Type" section for the options.

An example of "touchy" grout and mold cleaning.

White grout and glass block

Chosen because white grout is difficult

Mold on white grout

Cleaning with "Grout Restoration"

"Grout Restoration" brightens white grout

During cleaning with Grout Restoration

Sealed with Aldon "Same Day Sealer" so no change to white grout color.

Cleaned - sealed with Same Day Sealer


If growth returns:

  • Prove your grout and tile are really sealed (a water drop does not absorb if really sealed).
  • If it is sealed, evaluate the texture. Even though a surface is sealed, a textured finish could keep water drops adhered instead of running off. Try smoothing and resealing, if possible. A sanding sponge and/or #0000 steel wool might work for this.
  • If this doesn't solve it, you must have a constantly damp condition that never dries out. Perhaps increased air movement through the area will help.

Sometimes cleaning is a trial and error process. The cause of the problem might be different than thought, or have multiple causes and results that must be handled in steps. In rare cases, it cannot be cleaned. Proceed as though it is an experiment whose results must be evaluated.

Any Aldon cleaner has more than one purpose. It is not limited to only this cleaning project.