High mineral content tap water is commonly used during window cleaning and pressure washing services.
Tap water contains many different minerals such as calcium, magnesium, and silica. These minerals, and other undesirable materials such as fluoride, chlorine and metal ions bond with the minerals in the glass producing stains. These are essentially the same minerals and salts that you are attempting to keep from leaching out of precast during the stone cleaning and sealing processes.
When tap water evaporates, it leaves these particles behind to form a residue that is visible on nearly all surfaces. This residue can also change or hide the natural colors of precast and stone materials.
Deionized water is produced through a filtration process that removes the negative charge in the water caused by minerals and salt. Without these elements present, the water attempts to stabilize itself by becoming very aggressive, seeking negative particles in the form of dirt and other contaminants. The water then pulls these contaminates from the building, and washes them away. Without minerals and salt in the cleaning water, it can dry on the glass absolutely spot-free.
On-site deionization is inexpensive and recommended for all of exterior maintenance services. DI Tanks can be rented, or purchased, and are rechargeable. Using deionized water costs only a few pennies extra for each gallon of water used.
Below are 12 pictures of different glass stains caused by contact with high mineral content tap water and the use of dishwashing detergent in the window cleaning process.
Dilutable products work more efficiently when mixed with deionized water. The ingredients in Presto’s Stone Restore® Series are partially neutralized when mixed with the minerals in tap water. When cleaning or sealing concentrates are diluted with purified water, they are not activated until the product comes in contact with the intended surface.
When precast or stone is cleaned with tap water, excess minerals and salts remain on the surface and create an extra layer between the stone repellant and the minerals in the stone. We believe this weakens adhesion of water repellant molecules and results in an almost immediate leaching of chemicals from the material after sealing.
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