Ok guys, I am going to try to outline this so you understand how the deep sand bed works, how it actually reduces nitrates, and the beneficial organisms that live in the sand bed that eat leftover food, fish waist and other waist. The sandbed itself should be between three and four inches. You need to use sugar fine sand. This will not allow small partials to fall between the sand to the bottom giving you that black sludge that most get when they have gravel, or bigger grains of sand. Next, it takes time to seed a deep sand bed. This can take six months to a year. In this time you will still need to do water changes. The organisms that you need in the deep sand bed come from premium live rock. Critters like tube worms make their homes in the sand bed, and clean it. They live in the top one inch layer. Tube worms multiply very quickly as long as there is no predator. I have seen my tube worms catch fish poop and eat it, literally fighting over it. Below the first inch, inch and a half in the lower part of the sand bed is the beneficial organisms called (anaerobic bacteria) that consume the nitrates. They thrive in areas that have little to no oxygen. Since most aquarium critters don't go below the first inch, the anaerobic bacteria will thrive. The anaerobic bacteria strip oxygen ions off of nitrates to survive leaving nitrogen gas as a byproduct. Once your deep sand bed is fully established you will notice bubbles in the sand bed through the front of your glass. This is the nitrogen gas working its way to the top of the sand bed, completing the cycle of removing nitrates. The second part of making the deep sand bed work is having sand sifting critters that will also be part of your big cleanup crew. Nassarius snails, and cerith snails are best for this. I 1 per gallon my self, but that may be a little much. They keep the top layer of the sand bed turned over. While doing this, they are scavenging and also pushing sand down to the bottom layers of the sand bed for the anaerobic bacteria to do their part of the job. Like I said, once you have created your deep sand bed it can take 6 months to a year before you are ready to stop doing water changes. You will figure out when you are ready by testing. In the beginning when you are doing water changes, never touch the sand. Never siphon it. For me after six months I stop doing water changes and monitored with weekly water test. Now back to the big cleanup crew. Here's my personal list of what I have in my 24 to 30 gal tank. I have between 10 and 15 blue leg hermit crabs, 20 nassarius snails, 1 brittle star fish, 10 cerith snails, 1 turbo snail, 1 fighting conch, 2 smaller conchs, and a bunch of bristle worms. This sounds like a lot but remember I have no hair algae, or any other cleaning problems for that matter. The only cleaning I do is of my glass, and my filters. But, one thing to remember is that there is not going to be enough for a cleaning crew of this size to eat in this take. This is the reason why I over feed, to ensure that they have enough food. If they don't have enough food they will die. This will be for another form, but also remember when you stop doing water changes, you must dose different supplements. There is a lot that goes into this as well. Much testing is needed to understand and meet the demands of your tank parameters. You don't want to overdose, or under dose. Some people have a deep sand bed and still do water changes to replenish the trace elements. This is fine, just don't touch the sand. Please ask questions and leave comments. I know that I didn't touch everything, or go into a lot of detail so ask away and I will try to answer. Remember what works for me, may not work for you and do your own research before making any big decisions in this hobby. Thanks and have fun.