Tropical Hibiscus problem

I have a tropical variety 'Tiki Temptation' that was given as a gift last year. It grew and flowered well last summer, and I brought it in for the winter. It survived the winter inside and I set it back out this summer. It gets loads of buds, but just when it looks like they are about to open they fall off. I've given it some timed release fertilizer but it hasn't helped. Any ideas would be appreciated.

Spray w/ insecticidal soap to eliminate thrips which could b reason for aborted buds. Also stop fertilizing as too much nitrogen might also cause aborted buds. If and when plant normalizes, use a weekly diluted fertilizer specifically formulated for hibbies or flowering Tropicals

Thanks, I will give that a shot.