You really need to slow down some, you are trying to solve a problem that I don't think is there. You have not said anything about a rotten egg smell, you have not posted any sg readings and what do you mean by 2nd fermentation? Are you trying to do an MLF on a kit?
The smell you smell is probably just normal fermentation, 1118 can be a pretty aggressive yeast and could create off smells.
If fermentation is complete, I would rack and add kmeta and leave it along for a little while.