I've never fancied it much but the dc would love it That sums up holidays with teenagers!
I really wouldn't recommend the hotel we stayed in. Perhaps others will suggest somewhere. I would, however, recommend you stayed in PDLA or Los Cristianos because you are then 5 minutes by taxi from the water park.
We factor in two trips to a water park on a holiday usually. They offer discounted tickets for a second day if you buy them on your first visit.