Theres much better products out there now. Polyester resins will soon be obsolete for water effects. One to play with is Crystal Clear from Smooth-on. It has a fast cure, no odor and since its a urethane you can spritz or stir water in it for some different effects.
I would love to experiment with this, but at well over £30 a one kg kit(£46 was one quote

) I have been putting off, I suppose I will have to bite the bullet and give it a go !
I hope you USA guys can get it a lot cheaper.
John