2-2.5" is a tricky level, not deep enough to be a fully functioning DSB but too deep for a decorative sand bed and can lead to big issues.
I would reduce it to 1" or less and siphon and stir all you want or increase it to 5-6" and don't touch it or run the risk of exposing anaerobic and anoxic bacterias. DSB's are best left undisturbed and in low bioload systems where the bacteria can keep up. At 2+/-" you will have some bacteria but probably not enough to keep up with processing the waste and soon end up with a plugged mess full of detritus.
I would reduce it to 1" or less and siphon and stir all you want or increase it to 5-6" and don't touch it or run the risk of exposing anaerobic and anoxic bacterias. DSB's are best left undisturbed and in low bioload systems where the bacteria can keep up. At 2+/-" you will have some bacteria but probably not enough to keep up with processing the waste and soon end up with a plugged mess full of detritus.