I have a concrete bird bath that is very porous. I change the water every day and scrub it every other day but I cannot clean the indentations any more. I thought about sealing it after cleaning it with a pressure washer ( the only thing that cleans it). A Lowe's employee recommended to cover the basin with Quikrete concrete bonding adhesive. Does anybody knows if this product will do the job of protecting from future staining and if it is safe for the birds? I will appreciate any advise, all this scrubbing is bad for my arthritis. Irma