Skip on the gobys, they just disturb sandbeds and eat beneficial Critters.
Cerith snails are one of the best shifters. As they dig into sandbed they help keep the top layers of sandbed turning-over and oxygenated.
The best sandbed janitors are the small infauna, pods,worms,micro snails, crustaceans ect.
The problem is that gobys have a strong appetite for this creatures, thus your sandbed is a little inefficient.