[untamed]

Originally Posted by mr_alberta

WHat happens when the power goes out? How do you prevent back siphon into your sump? Also, how do you balance it out that exactly the same amount of water is draining back into your sump vs being pumped out of your sump?

These are the reasons that closed loop systems are closed. If you attach it into your return system, it isn't "closed" anymore. If there is a power failure, the system would back flow down to the level of the "closed" loop tank inputs. (likely overflowing the sump and pretty much draining the display tank).

You could stop the backflow with a check valve, but no one wants to be THAT dependent on a check valve.

I wouldn't recommend this idea....but I've never tried it myself.