Frequently Asked Questions: The D/2 Difference
At Legacy Stone Preservation, we don’t just clean headstones; we conserve them for the future. Central to our process is the use of D/2 Biological Solution. Below are the most common questions we receive about our methods and why we choose professional-grade preservation over “quick fixes.”
What is D/2 Biological Solution?
D/2 is a biodegradable, pH-neutral liquid cleaner that is specifically designed to remove biological growth (like algae, lichen, and fungi) from masonry and stone. It is the only product trusted by the National Park Service and is used on our nation’s most sacred monuments, including the White House and Arlington National Cemetery.
Why don’t you use bleach or pressure washers?
Our #1 rule is: Do No Harm.
The Danger of Bleach: Bleach contains salts. When sprayed on porous stone like marble or granite, these salts get trapped inside. Over time, they crystallize and expand, causing the stone to “spall” (the surface literally flakes off). Bleach can also lead to permanent yellowing.
The Danger of Pressure Washers: Historic stones may have hairline cracks that are invisible to the eye. The high-pressure water can enter these cracks and shatter the stone or blast away the delicate inscriptions.
How does the cleaning process work?
Our process is a combination of science and manual labor:
Hydration: We thoroughly pre-soak the stone with water to ensure the cleaner stays on the surface where it’s needed.
Application: We apply D/2 and allow it to dwell, breaking down biological bonds.
Agitation: We use soft-bristle preservation brushes to gently lift away surface grime.
The Residual Effect: D/2 continues to work long after we leave. It stays active within the pores of the stone, working with the sun and rain to continue brightening the monument for weeks and even months.
I saw the stone turn orange or pink during cleaning. Is that normal?
Yes! We call this the “Magic Glow.” When D/2 reacts with certain types of biological growth—especially on older marble—it often turns a bright orange, pink, or yellow. This is a chemical reaction that proves the biological matter is being killed at the root. This color is temporary and typically disappears within 24 to 48 hours.
Will the stone look brand new immediately?
While our hand-scrubbing provides an immediate and dramatic improvement, the full results of a D/2 treatment take time. Because it is a “gentle” cleaner, it continues to lift deep-seated stains over the following 3–6 months. A stone cleaned by Legacy Stone Preservation today will actually look even better six months from now.
How often should a stone be cleaned?
In the humid climate of the Golden Triangle, biological growth returns faster than in other regions. We recommend a full professional cleaning every 12 to 24 months, or enrolling in one of our Ongoing Maintenance Plans to keep the site pristine year-round.
Preserving a Legacy?
Don’t risk damaging your family’s history with DIY methods. Trust the professionals who use the right tools for the job.
Call or Text: 409-939-4092
Legacy Stone Preservation 