AWC with adjacent tank

[LobsterOfJustice]

I have two tanks on my desk, one is an 8" cube and the other is an Fluval Spec 16. I'm struggling to get the smaller tank to stabilize & establish, and it continues to get covered in cyanobacteria despite no feeding or other nutrient inputs (coral only in this tank) and using the same water source as the Spec 16. In lieu of plumbing the tanks together, which would be complicated and require drilling, I'm considering setting up an automatic water change to simply exchange some water volume between the two tanks regularly. Has anyone tried something similar or see any reason why this wouldn't work to stabilize and reduce maintenance on the smaller tank?

 

[ReefStable]

In theory, if all is well and calibrated, it's fine. The gotcha is when one of the pumps fails, something clogs, or they're out of calibration. Then one tank is losing water and one is likely going to overflow.

I thought about something similar and that was what stopped me. By the time the safety equipment was in place, it'd be cheaper and faster to drill and plumb.