Clear Lacquer

• Clear lacquer offers a wet look to simulate a rock found in a natural waterfall setting. Easy to paint on individual pieces, lacquer also acts as a sealant for artificial rocks, and maintains balanced water chemistry in the installation. Clear lacquer sold at hardware and paint stores includes algae-growth inhibitors to keep your waterfall looking pristine.
  
  

Water-Based Paint

• Water-based paint found at any hardware store will allow you to make natural, rock-like patterns on artificial rocks. You also can get creative with the waterfall rocks, choosing your own color combinations and patterns. For a multi-colored, layered look, you must apply the paint in a fine mist via a pressurized sprayer filled with watered-down paint.
  
  

Epoxy Paint

• Epoxy paint is a colorized coating consisting of two basic materials -- the pigmentation and the hardener. The pigmentation provides the color, while the hardener sets the paint for a lasting finish. The hardened surface will inhibit algae and bacterial growth while resisting erosion from the force of the water.
  
  

Foam Coat

• If your waterfall's artificial rocks are made of foam material, you'll need a specialized foam coating as a protectant. Such coatings usually come in powder form, and must be mixed with water before you apply it. The coating will help the foam withstand the force of your waterfall, so it will continue to look how you first envisioned it. Sanding the coating mimics the natural appearance of a rock structure.