What are these tubes

[Tfain]

What are the tubes that are coming out of the top

 

[Tfain]

It's the small tube my hands on in this pic

 

[rdnelson99]

If the main pipes are the overflows taking water down to a sump then the small tubes are there to hook to a vacumn pump or a power head. When you have a power outage and lose the siphon, you need a way to remove the air at the top of the main pipe or the siphon will not start on it's own. If that were to happen, the pump in the sump will pump water to the tank but it will have no where to go except to overflow the tank.

 

[rdnelson99]

Here is a good explanation of how an overflow works.

Melevsreef.com - What is a Sump?