Hi all, Need some guidance on how to clean the bio balls in my wet/dry sump filter system. My tank has been up and running well for 1 year now but I have been noticing a slight rise in my nitrate level. I know the use of bio balls contributes to increased nitrate levels over time and the most ideal situation is to replace the bio balls with rubble rock. I have the following questions: 1) What procedure should I follow in cleaning the bio balls? (clean all at 1 time?, rinse in saltwater vs. freshwater, scrub with toothbrush, etc?) 2) If I wanted to switch to rubble rock, do I replace bio balls all at once and swap out with rubble rock? 3) Do I have to let the rubble rock cure first? (LFS sells rubble rock that has been in their tank for some time now). 4) LFS also sells dried rock at a discount price ... can I break these up, clean them, and immediately use them in my sump even though they are not "live rock"? Thanks for your help ... things have been going very well with my aquarium and I don't want to mess this up by doing something without researching first.