Kids are not allowed in indoor pool!

This is the first time I've ever left a negative review, but I was left angry & frustrated by our experience at Hotel Botanico. We specifically chose this hotel for its indoor pool; having visited Tenerife at Christmas before, we knew that it might be too cold to swim outside even in a heated pool. The main thin out kids love to do on holiday is to swim. We were therefore perplexed and very disappointed when we arrived at the pool entrance, on Christmas morning, only to be told (rather officiously) that no children under 16 are allowed. I asked to speak to the manager about this and was told she was unavailable, so I wrote her a note explaining that there was no mention of this restriction on the hotel's website so far as I could see and that, had we known, we would have booked a different hotel. We received no acknowledgement or reply to our letter during the remainder of our stay, which I find staggeringly rude. All we received was a standard letter urging us to use the kids club; our older daughter, aged 15, was too old for this (which caters up to 14) and yet too young for the indoor pool, so it really felt as though there was nothing for her. I completely understand that a hotel may want to exclude children from certain facilities but this must be made clear when booking. (We even received a welcome letter addressed to the family telling us all about the pool & other spa facilities, which didn't mention that only half the family could use it!) I also feel very strongly that a hotel manager has a duty to respond to issues raise by guests.