Screwed up water profile: Can it be fixed?

I just realized that I totally screwed up the water chemistry on my last brew. I was in a hurry and plugged in some wrong numbers on Palmer's spread sheet.

Bottom line is that I was making a Czech Pils, shooting for a Residual Alkanlinity around -60 and ended up adding WAY TOO MUCH CaCO3 and the RA was 193.

Just a little off, right? It's been fermenting for a week and I just realized the mistake. I haven't tasted it yet, but I know it's going to be the most harsh, bitter taste ever. Correct?

Anything I can do to fix this now? Even if it means diluting the batch a bit? I know the first step will be to taste it, but I know what to expect. First big brewing screw up in a long time. Thoughts?

The good thing is that CaCO3 is not very soluble in water. So it probably didn't significantly affect the beer. The real problem is the lack of acidification that was needed to promote a proper pH. I can't even understand how chalk was a candidate for water treatment if your goal was to reduce RA to -60. Possibly you need to revisit the software and advice you use for brewing water adjustments?