Pantera Floods

[stackny]

Guys, Im having a lot of trouble getting the tuning for Pantera's Floods. Step and a half down I guess? I keep thinking Ive got it but then I find out its wrong. How should I go about tuning this way?

Thanks
Stack

[pogohead]

detune a step and a half and start at the 4th fret, A (F#) string :)