What I do to germinate seeds is put them into a cup with distilled water .... I put them on my flower level because it's warm there and cover them so no light gets in. In 24-48 hours they sprout. I use a spoon to carefully get the seed and place it in soil .... in your case rockwool.

I don't add anything .... if the seeds are good they usually sprout within two days, but for some that take longer I change the water every two days.