Closed loop without drilling?

[mfinn]

I've done 2 over the top closed loops on 2 tanks.
Both setups had a suction pvc pipe and both went to sea-swirls.
Worked pretty good.

 

[abc123]

So I’m thinking of adding a closed loop system to my tank to replace my power heads. Reading, it seems like closed loops are usually drilled in through the bottom of a tank, and also used a lot on larger tanks (not finding much on smaller tanks). That said, I have no plans to tear down my tank to drill it to run the closed loop. So my questions are as follows:

Can you run a closed loop over the top edge of the tank?

My plan for this would be to run the pvc around the top rim (hidden by the rim of the tank since it’s not rimless) and then run 2 lines down the back behind the rock work for flow back there.

Am I completely missing the concept of the closed loop or will my thought work?

Did you ever go though with this idea?