2-part mixing question

[BirmJam]

I just mixed up a new gallon of calcium and needed to use 40ozs to get my level up. Can I mix up an additional 40 ounces and add it back to the gallon?

 

[soccerbag]

As long as the mixing solution (calcium vs. RO water) is the same, it would be fine. I would just mix up another full batch and then just keep it in a 5 gallon bucket for later use.