Uglassit Gelcoating

[mrmumbels]

i recently bought some gelcoat from uglassit.com and was wondering if anyone has ever resurfaced their pool with this or any other gelcoat. my concrete pool was resurfaced with fiberglass by fibre tech 15 years ago and i'm looking for the best possible way to get the gelcoat to adhere to the substance they used which i'm told is a polyester resin. I'm told i need to sand it down and make fine grooves to make this tuff stick but am clueless to how deep these grooves need to be to make this stuff stick the best. Most of the final coating that was applied by fibre tech has fallen off and is showing the blue undercoating. But there's still many spots, (mainly the edges to the fiberglass) that seem to have a really thick layer of this top coat that has not fallen off and doesn't look liek it'll be possible to sand off due to it's thickness. Where the final coat has fallen off it is blue as i stated and there is a bit of fiberglass showing which i'm sure the gelcoat will have no problems sticking to. As for the spots with the fibretech final coat still intack i'm curious to if this gelcoat will stick because i can't see much fiberglass strands sticking through. Did i mention my pool is empty and the gelcoat gets delivered in 3 days? I really need ot get this done this weekend. Any advice would be great. I could post pics of the blue and white surfaces if anyone would need to see these.

Thanks,