GTi 8v Brake Fluid Level

Hi there,
My golf seems to have a very gradual brake fluid leak. Can't see any obvious leaks, but the level keeps dropping below the min mark and its very gradual - should I bleed the system or could it be another problem? Also, what brake fluid should I use?
Any help /advice appreciated!

 

use dot 4

you must have a leak...leaky caliper or pipes/hoses its pretty dangerous so id suggest you get it looked at

 

Have you just rplaced the fluid could be its leaking in the master cylinder past the seal