Replacing shampoo trays
A property management company called me and said one of their rental customers had a shower where the shampoo trays fell off and hurt the tenant's arm. They also wanted both trays replaced with black ones to tie in with the accent. And they did not want circular ones, instead they wanted more triangular shampoo trays.
These old trays had fallen off for many reasons. First, the opening made by the previous tile setter was too small. Second, he didn't make indentations into the mortar bed to so that the glue would key into it the mortar bed and hold up the tray. Next he used grout instead of thin set to set the trays and lastly, he didn't fill the holes in the back of the trays with thin set (glue).
I purchased HCP high quality shampoo trays in shiny black color and enlarged the openings in the wall to accommodate the new trays. These new trays were set correctly into the openings and will last for years to come.