If you don't want to sleep at Ersfjord beach, and would prefer to have a couple of comforts, Skaland Camping has pump out sites, water for washing your dishes, restrooms, an a convenient location in a small village that's set right by the water.
The facilities are only for people who are staying there, and we actually paid for the cheapest campsite just so we could pump out the tank and fill the campervan with water!