My pool is fibreglass covered cement - and has a very small 1mm or so crack around the weir.

What would be the best to fix it with - I am thinking ether fiberglass (never used it before though - would I need to prep the surface at all?), marine silicone (not sure how long it would last) and my favourite - 2 part bostic epoxy.

Kind of think the epoxy would be best - any ideas?