What did you see, when you first performed it, and what did you see when you used the other one. Also, you could be more clear: what compound did you use first, and what was second? Your term "magnesium nitrate-6-water" is not the usual one we use, can you use this forum's buttons to draw out a correct chemical equation, or at least start one?
I'm not trying to be obtuse, this is how we help on this fourm, we give hints, and try to help you solve the problem for yourself. You're better off, that way.