Crank the export back up and I would suggest a detrivore kit over snails alone. The microlife in the sandbed is far more important at keeping things healthy and actually pound for pound turn the bed much more than snails alone digging through it.
While trying to tread around the debate scenario, a DSB
is like every other tank. Export and waterflow are still vital the same as bare-bottomed, shallow sandbed, etc. The misnomer was that they were initially thought to be undestructible and people way overfed and didn't pay much attention to the life in the sand. It was only 4 years ago when I set my first up that a national magazine even stated you could not overfeed with a sandbed.....that was the failed misconception, not the sandbed itself.
They have an obvious drawback just like all other systems (ying to the yang I suppose). You get denitrification, but the price is you have to maintain the bed by replacing diversity from time to time.