2014 Moomba Mojo Center Tank leak

I'm trying to diagnose a leak in my center ballast tank and am trying to determine what the 3 hoses on the tank are for.
- 1 at the bottom rear of the tank is the fill/drain line, I assume
- 1 at the top rear of the tank: overflow?
- 1 at the top front of the tank: overflow?

If one of those is for overflow, what is the 3rd one for?

The center underfloor tank has a front overflow that goes to the bow bag.
If you do not have a bow bag, then it should be plugged or going to an overflow out of the boat.

Thanks, I'll verify today.

My boat came with no bow bag. It appears that the front top hose runs back to a t-fitting, near rear of the tank, where it is joined to the hose from the rear top and those continue to the overflow on the right side.