What an awesome idea! I had a hard time getting my nitrates down and I am darn proud to say they are at 0! I started with a crushed coral substrate that had a Cal Spiney Lobster living in it who was a pretty messy eater so it was really bad when we switched it over. Then we made the mistake of putting live sand over that. Yeah, not good, the nitrates were over 100 at that point.
We ripped the whole tank down, took out all of the crushed coral and sand and then replaced it with fresh live sand and rearranged the whole thing. We then began a series of 30% or so water changes every week untill it was below 40 then every other week until it got down. I have something around 150-175 lbs of live rock and a DSB that ranges from 4-6 inches in a 110 tall. I also have chaeto in the sump. My water drains into the sump into a filter sock to catch the big stuff that I try to change every few days or more depending on how it looks. There is additional sand and rock in the sump. I have a skimmer rated for a tank twice as big and that's it. No chemicals for nitrates or other filtration.
I think that what has helped me is that I have added fish at a super slow rate, I only have two in there so the system has a better chance to catchup when the bioload increases. I also don't feed super heavy, and I have Bob the Diamond Goby and a few Narcassius snails to keep the sand clean of debries.