This was one of the very first liquid yeasts I used when brewing with them. It works well in PA's and IPA's @ around 22c if you want something a tad fruitier but 18 is the ideal temp.
Great yeast. My favourite. I use it in all my American and British Ales. Make sure you have some head space in your fermenter too. When they say this is a true top cropping yeast they mean it.
Bear in mind Rook if its reading 18 degrees on the outside of your fermenter I'm sure its probably chugging away at 19-20 on the inside at high krausen anyway. Worth bearing in mind.
Note unless your temp control or thermometer is in direct contact with your wort it could be relevant.