My beautiful slate! It's watermarked and stained! If you remember, last week I sealed the slate with a penetrating sealer. Apparently, I didn't follow the directions well enough, because this happened!
The directions call for pouring the sealer on, waiting 10 minutes, and wiping the excess off. This seemed like a huge waste of sealer, and somewhat impossible with individual tiles, so I opted to brush it on a few times, wait until the stone was no longer soaking sealer up, and then wipe off the excess sealer. That's what I get for not following instructions!
I have bought a bottle of sealer REMOVER. The current plan is to install the tile as-is, and then treat the whole floor with sealer remover. Then, re-apply the sealer using the EXACT instructions! Sigh.