freshly mixed salt water is not yet ready to add to the system as it is not yet throughly mixed. freshly mixed salt water is somewhat caustic and may percipitate calcium out or buffers making it hard to keep your calcium and Ph stable. you should mix your new salt water for preferably at least 24 hrs at tank temperature, and if you are using ro or di water you will want to oxengenate the water vigerously also. also if you are using ro/di water you may want to consider a reconstitution additive such as kent marine osmo prep before adding your salt. to reconstitute the base for your salt mix. hope something here helps.
