Hi. We have a new fiberglass pool (installed last Fall) with a paver coping. We have several 'holes' in the mortar joint under the coping and, although they are fairly small, I am concerned that water is getting into these spaces (not to mention it's aesthetically unpleasing). What is the best way to fill these holes? Can I use a silicone caulk or something similar? Thanks on advance for the help !