Can I Use Synthaproof to Seal a Concrete Block Pond?

Sealing a Concrete Block Pond: Synthaproof vs. Dry-Lok

Synthaproof? Unknown. Call the manufacturer — ask if it's non-toxic to fish/plants when cured.

Critical Rule

NEVER use oil-based sealers. They leach toxins indefinitely.

Proven Alternative

Dry-Lok Latex Base (Home Depot) — water-based, fish-safe when fully cured (7–14 days). Used successfully by many pond builders.

Application

• Clean, damp concrete.
• 2–3 coats, proper cure time.
• Fill, dechlorinate, test before fish.

If Synthaproof is oil-based — don't use it.