Overflow guard?

[Reef.]

My Royal Gramma has decided he likes sleeping up against the overflow, as my tank is only a 14g aio, this causes the ato to overfill the tank, is there any device out there to put in front of the overflow to prevent the reduced water going into the overflow from slowly down, which in turn triggers the ato, lowing the salinity.

 

[GoVols]

My Royal Gramma has decided he likes sleeping up against the overflow, as my tank is only a 14g aio, this causes the ato to overfill the tank, is there any device out there to put in front of the overflow to prevent the reduced water going into the overflow from slowly down, which in turn triggers the ato, lowing the salinity.

Some of these plastic coils come to mind:

Amazon.com : spiral binding coils