You need to put a final coat of food grade or potable water grade resin on the inside. Industrial resin will off gas into the water. Check with your a local paint dealer to see if they have any or know who does. I believe Sherwin Williams sells if over the internet as they carry it in thier shops or can order it but not sure if they ship to Sweden. First call around to local paint dealers and see if they have anything if not do a search on the net for "food grade" or "potable water grade" resin