I have about 100 pounds of LR in my fuge, and another 80 in sand. The extra space is full of macros. I put the majority of my clean up crew down there to process floating foods that make it downtown. Never once have I had a nitrate problem. You will need to remove all of the rock at least once a year, and rinse it in RO/DI. Then you will need to pick out the macro and janitors. Then, despite all warnings heeded to me, I stir all of the sand many, many, many, many, times. Everytime, I take out detrito-water (aka chocolate milk) and keep doing it till my water is starting to clear. You will need to add saltwater to help give enough to fully flush your system.

It will make your tank EASY. EASY. oh,,,,, EASY.