The pool. Ten pools in all, including a heated indoor pool and a children's indoor pool; the water park slides are heated from 1 April to 1 May and from 15 to 31 October.
The hot tub. Whirlpool bath listed by Hotels.com.
Hotels.com gives it 9.4/10 from 192 reviews; I haven't read any reviews about the water temperature.
Guide's tip. In spring and late autumn, rely on the heated indoor pool.