can't connect two hard-drives to my airport I have two seagate usb 3.0 4tb drives full of music that I want to access wirelessly. I have my Bites USB 3.0 hub powered by DC 5V cord. I want to connect these to my airport extreme (5th gen), but there's a problem. 

When I connect the whole thing to my airport, it says that the hard drives need to be repaired. When I connect them (via usb hub) to my Macbook Air, it can only see one hard drive at a time (the first connected), but all of them work (as if they're not broken, my Mac sees both when I plug them directly). So obviously - there's something wrong with the usb hub. But what exactly? How can I fix this?
If the USB hub is bus powered (it doesn't have to plug in to a wall socket) then the problem is that your Hard Drives are drawing too much current. USB Standards state that each USB port needs to be able to output 500mA. 

When you divide that by four (assuming your USB hub is 4-port), you get 125mA, which isn't nearly enough to power two hard drives.

I suggest you get a externally powered USB hub (one that requires a power supply other than USB), as that will ensure that each USB port receives 500mA each.