I am new to this forum and find the posts extremely informative, if you have the time I wondered if anyone could point me in the right direction in regards to a very small project I would like to do. I would like to build a small water feature/pond in an alcove on my balcony, I was thinking of using Q Con blocks at the front of the alcove thus making a rectangular feature. This would leave me with an existing tiled surface on the bottom and existing plastered and painted sides and back, in addition to the proposed Q Con front. The whole project will be only around 600mm x 1500mm x 200 mm, I would like to tile the inside of the feature (including the bottom if required) with say a black slate type tile. Obviously it will all have to be watertight, any ideas especially in view of the 3 different surfaces involved ? Your help and time in this matter would be most appreciated.