My neighbors gave me a very nice 5 person Morgan Spa. It's sitting in my carport pending it's permanent placement in the side yard. I was cleaning it out last night and discovered a hairline U-shaped crack in the corner at shoulder level when sitting in the corner seat.

I don't believe it goes past the acrylic surface because it's such a fine crack. Any suggestions on how to deal with this?

Thanks.

Hairline cracks are common with older spas. If it doesn't "catch" your finger when you rub across it, you can just let it go and be happy. If it does catch your finger, you can wetsand it down and polish it using automotive swirlmark remover to get the shine back. Otherwise, you can consult a professional that does bathtub and other fiberglass refinishing.