concrete crack repair

Hello all, We purchased a home last year with an old concrete swimming pool, probably from the 80's (36 x 16 x 9) that is in need of some repairs and refinishing. We are located in Quebec, Canada, were winter temperatures can drop below -30c (-22f). I have read everything I could find about...

I have a crack where my concrete coping starts in my salt water in ground pool just above the tile line. What would you recommend I use to repair this? It is fairly small but I am looosing water and concrete debris fall into the water when the kids make waves and it slowing getting larger.