Question re: back of tank - keep glass clean or not?

[naesco]

In my opinion never clean it.
It may look picture perfect if you do clean it but here is the downside.

Many reefers take care to remove detritus from the bottom of their tanks. They also take care to stop any non-macro algae, small outcropping of cyno from growing their tanks.

By leaving the back of your tank alone, tiny crabs, shrimp, pods, bacteria and many many other critters have a place to home and to eat and avoid being eaten and breed.

These critters are food or provide food through their eggs and larvae to the corals and some of the smaller fish in your tank.