I also needed to add I got the tank and sand used and did not know I should have rinsed the sand off after the move. They had put the sand in a big trash can and we moved sand with water to my house and they just put the sand and water back in the tank. I have done a 35% water change and the levels are still high. I am going to do a 50% today and was thinking I should either rinse the sand or replace it all together. What should I do?