Has anyone had experience using large boulders or large shale rocks in a water feature? We are looking at a job now where the customer wants to basically turn a natural shale/rock wall into a water feature. A few items of concern: Will the constant water cause the shale to flake? Can an epoxy sealer prevent this? Is there a commercial cleaner available for cleaning the stone initially? Can the rock be bored run hoses/wires? Any help or direction would be greatly appreciated.