We have a small rock waterfall beside our concrete pool. The waterfall works great, but I notice a bit of water dribbling back behind the waterfall and into the garden. This is coming from where the PVC pipe feeds into the rock.
Is there something I can trowel/pump around where the pipe feeds in to seal this up?
Could I just use some regular mortar here? Just pack it in around the pipe and it will do the trick when it dries out? Or could it crack the pipe as it cures (I'm not sure whether mortar expands/shrinks as it cures etc)?