Does anybody on this forum know how to purify shadow lugia?

Either Purify all the Pokemon in the game or fill up all nine tempo thingies. I'm pretty sure it's the first one, but Serebii said to do the second one. =\

Ok its like this

step 1-catch lugia

step 2-fill all the gauges in the purifiing machine full

step 3 put lugia in

step 4-He gets purified- auto! just
remember! all the spots in the purifiing machine
has to be perfect!
step 5- Do what ya want with lugia, hes not shadow anymore!

P.s. I have him in firered with this trick!