1 week ago we had a bad leak in our 115g reef tank. Our LFS delivered us our new 120g tank and even helped with all of the install. The old tank was a DAS tank that held all the crap in the enclosed filter which the LFS told us could be the reason we could never get control of the nitrate problem. We spent a million bucks on water changes it seems but it never went down. They gave us a product in a baggie to go into the sump ( sorry can't remember the name ) to eat the nitrate. We got so excited a few days later when the test showed almost clear of nitrates, but about 15 min later it was pegged over again. Before, it was immediately pegged over the top, off the charts high. So does that mean any improvement at all or no? We are new to the sump way of life...what do we do? What do we use to get rid of this crap?