Rain wont have any real effect on the chemistry...Except mybe provide a bit more aeration due to the rain drops splashing in the water.
You will be fine.
And yes, test and just add only what is needed. There is really nothing more to it than that!
You will be fine.
And yes, test and just add only what is needed. There is really nothing more to it than that!
It also looks like it might rain Saturday night. How does that effect everything? Or do I just test and add things as needed?