I saw on your interactive card that you find water in Croatia to be excellent. I dont know about your standards in your country, but you cannot make classification based on Your own perception of excellent. As the best water or top of scale should be water which is the best in whole europe, first of all you need to find this water.
For example saying that water in Zagreb is excellent is out of mind, because comparing to water in lets say Rijeka it is toxic, polluted and unhealthy. But obviously for the water in your country they are both excellent, but they are far to be considered in same category. It is known fact that most people from Rijeka when visiting Zagreb do not drink their water. This is just one example.
Other thing much more important is your wrong classification of sea water. For years you give polluted beaches blue flag in my country there is also local saying that you can buy blue flag from you for some sum of money. If there was real law your agency would cease to exist and you would all be punished. Not just that you give blue flag on beaches in or near major cities and refineries, but you dont even consider the waste waters in small towns, which dont have basic lenght of their exhaust in sea. 90% of your classification is wrong, and this gives people and tourists false knowledge of where they are and how safe it really is.
If you dont know what clean sea is then you are by no authority the ones who can make any classification. Personally on 20 beaches that have blue flag which are the nearest to my home I would consider safe and clean none, also your blue flag is reminder not to go anywhere near.