Planet aquarium internal sump drain pipe help

[skypham817]

I’m trying to plumb my 215g planet aquarium. I see only 4 holes. 2 return and 2 drain. Does planet aquarium tank doesn’t have emergency drain? Does it use both of drain? Or just 1 primary drain and 1 for emergency drain? Thank you in advance

 

[UncommonSense]

It is a Herbie style drain; one primary drain, one emergency drain!