How Do You Clean A Sandstone Water Feature?

Question

I have a large sandstone ball water feature. Over the years (approx 11) it has become very discoloured and dull. We have tried various algae solutions, scrubbing, even sanding but cannot get it clean. The picture shows it just Commercially pressure washed and scrubbed with a bleach solution, what else can I do and how do I prevent further discolouration, if it is ever clean again, should it be sealed somehow?

Answer 1

Sandstone is very porous so take care not to use any acidic cleaners as they will eat away the stone. Do not powerwash. The best thing to use is dish soap and warm water. First apply warm water and let it sit for several minutes to loosen dirt. Then gently brush dirt aside with a cane broom. Then with warm water and a few drops of dish soap, scrub the stone with a brush. For tough stains, use a paste of baking soda and water. Allow the paste to sit for several minutes before scrubbing. Once your sandstone is clean, apply a topical sealer.