I have such a thin layer of CC that trapping the detritus isn't really an issue for me. I also try to have a lot of water movement in the tank including at the CC, so all that will get turned up anyway. I do worry that with sand and the current that the sand will stir up and cause a mess. I am moving in a few months and will probably change it to sand, but not a deep sand bed. I will probably only put a 1" layer - more for looks. I have an ecosystem that has a sand bed about 2 1/2 - 3 inches deep. I'm probably going to add to that when I move. I have no objection to dsb at all, I actually believe in it, I just don't think it is necessary, especially with my sand in the ecosystem. I've had my tank for 4 years and have never had a problem or elevation of nitrates. If I were to start from scratch, I would go dsb, but not if I don't have a problem now. Plus I have way to much money invested in this tank now that I wouldn't even risk the ill effects of a possible cycle when moving, if I chose to do the switch then.
No, I don't work and have never worked at the store, just been here for the last seven years and going there for 4-5yrs, so I've seen them come and go. Wasn't trying to sound like I was selling the store or anything, they just happen to be the rare family owned store that actually cares about your pets, etc.
I'm not convinced about the skimmer taking good nutrients that other systems won't. I would never go without the skimmer. I did for a while, and nothing but trouble happened. But, that's not to say you can't. Some people never skim and never do water changes, and make a good case, but I just don't think that we will ever be able to reproduce the ocean. The ocean happens to be so big that you don't need a water change! I don't think that aquariums can ever simply recycle everything in the water, no matter how much we try.
Can't speak for mangroves, don't know much about them.
For anybody - as for my question above, will current stir up the sand if I put around a 1" bed?