I ran bare bottom for a while, hated the look and eventually added fine sand with much less overall flow to compensate. I took it all out after 1 week because it was a nightmare. Even at 1/2” depth, I started getting anaerobic areas and hydrogen sulfide bubbles forming. This was with sand sifting stars, nassarius snails and enough flow to keep my acros nice and happy. Having sand constantly covering my montis was a factor too. So out came the turkey baster to knock out the detritus. Lo and behold, just like with courser sand, tons of detritus came out! This is pretty much the case with every type of sand i’ve ran. Either way you’re going to have to maintain the entire sand bed if it’s shallow, or just the thinest layers of a deep sand bed and hope it doesn’t disturb the nastiness beneath. This will make heads spin and generate “you can’t do thats!!”, but I run a mix of carib sea special grade and crushed coral aragonite (dun dun dunnnnnn). I was recently pushing 80x turnover through the tank and even the special grade was still blowing around after months of settling. I plan on upping the flow even more soon. My nitrates hold steady at 5ppm (right where I want it) just as they did with my fine sand or bare bottom and now with crushed coral because I still regularly mechanically remove detritus (bi-monthly for me). I just swish the crud into the water column where it gets sucked down the drain and into a filter sock. The sock gets replaced with a clean one every week anyways so no big deal. This takes around 5 minutes on a 100 gallon display. Maintenance is the key here and honestly one type of substrate doesn’t take any less maintenance than another in most cases. IME, I really don’t see one substrate or a lack of substrate being inherently “cleaner” than another. Which brings me to the “ah ha!” moment in this hobby when I used to have nitrate issues even though I did all of the “right things” like frequent water changes, less feeding, etc. I was siphoning my sandbed probably every other month and expecting my CC to do the rest. It wasn’t working and my nitrates had crept up to 30ppm with noticeable hair algae on the rockwork. I started my current turkey baster routine and now nitrates and nuisance algae really aren’t an issue for me anymore. As a matter of fact, I’m actually doing far less water changes in order to keep nitrates in the tank.