Green pool forever resorts

Arriving on the 7th of January to Gariep Dam forever resorts and to a dark green pool. On the website it clearly advertises a blue pool. (False advertising). When confronted with the issue The manager is unwilling to help, he stipulates that it's fine to swim in. I mean who wants to swim in a dark green pool for a holiday at a resort? The manager then blames weather conditions and offers to help find us alternative accommodation. What customer service is that? The resort could have informed us beforehand of this issue, especially if one is paying a large sum of money to stay there.