Yes the pool is in Koh Samui ; at least this is what we could guess from this picture.
I never went there despite some good information we read here and there about gay nightlife in Chaweng. Samui is not yet in my plans for my next trip (just booked my flight at a reasonable rate but still a long time from to-day).
By the way I opened a Twitter account (see link in the upper right corner of this page) but I am not smart enough to be sure it will be useful or not ...