I am also not sure when I should hydrate a new batch of yeast. Have used QA23 yesterday and will change to EC1118 which has a tolerance to higher SO2.
I just checked the tanks and the 42 gallon has some bubbles on the surface. Will check again in an hour and if it has increased will add Fermaid O yeast nutrient.
Any thoughts ?
jeff
Agree with @Chuck E , get the SO2 down before you try to proceed with yeast and / or nutrients. You can add nutrients once you get fermentation going.