Well, mine kind of smells like the ocean. Every few months I remove the
LR rubble and vac out the sedement on the bottom. I ussualy clean the filter pad and plumbing as well. A few months ago I was having a small nitrate problem. One of the things I did was to replace all of my bio-balls with
LR rubble pieces from the
LFS. Bio-balls are great at converting nitrite to nitrate but do not work great at removing nitrates.
LR rubble takes this a step further and successfully grows bacteria that removes nitrate. I have noticed a significant decrease in nitrate since adding
LR rubble.