Are your lenses clean, and in proper place?
9.

Are the tablets in focus with the ground-glass?
If you can attribute the failure to none of these, mix a new box of some other kind of quick, say the dry, for instance.

If you fail in the same manner here, take time, wash your buffs, overhaul all the chemicals, and start anew.

Do not be discouraged.
There is no day so dark but that the sun will shine again.

We will close with this brief summary of advice: Clean your plates.