The waterfall has been off for 2 days now and the pool level is holding fine. A close inspection of the waterfall shows a couple of places where there is heavy enough efflorescence that I think this may be pointing to where water is getting behind the rocks. In both spots, a bit higher, there was a spot or two where the grout between the rocks might be bad. The waterfall only runs about 2 hours normally this time of year and so those spots would have to take a lot of water to make a difference in the pool in a weeks time.
Now the question is how to seal this. The grout between the rocks is colored brownish. The pool builder says it is "chocolate" color but I cannot find that concrete/grout color at Home Depot. I got some "brown" but We do have grout in a tube, not sure what color, maybe just grey. In order to use this grout in a tube I guess I need to chip out some of the grout to make it larger and have a chance to hold on there. Or maybe I just want to use clear silicone caulk? I also have 2 part pool epoxy but it is white, I don't know if the concrete color could be added to that to color it.
Does anyone have any advice on this?