I'm having a hard time understanding this and I can't run the spread sheet on my Mac.

stupid Mac

But let me try to explain this:

you have alkalinity worth ~130 ppm CaCO3. This also means that your bicarbonate content is worth 130 ppm CaCO3. Now you only have Calcium that is only worth 110 ppm as CaCO3. Since the lime treatment bascially causes the calcium and the bicarbonate to form chalk (CaCO3) your water only has the ingredients for 110 ppm CaCO3. Your calcium is the limiting ingredient here. The nice thing about lime is that you don't have to consider its amount in these calculations since all the added lime will also precipitate as chalk. It's almost acting like a catalyst.

Now that we know that we need to add more calcium we can try calculating it. Let's say we want to precipitate all alkalinity worth 130ppm CaCO3. This means we need at least the same amont of calcium. But we also need some calcium left over such that the brewing water can have at least 50 ppm (actual 50 mg/l) calcium. Those 50 ppm are worth ~120 ppm CaCO3. To put it all together: the starting amount of calcium needs to be 130 (needed for alkalinity precipitation) + 120 (desired left-over in water) = 250 ppm CaCO3. The water starts with calcium worth 110 ppm CaCO3 hence we need to add 140 ppm CaCO3. This equals a calcium addition of about 56 mg/l which you can get from about 240 mg/l gypsum or from ~200 mg/l calcium chloride.

Calculating the lime is a bit more difficult since you need to consider the chemical reactions that are happening and you also need to condider the residual amount of free CO2 and carbonic acid in the water. For this you need the water pH. Assuming a pH of 8 I see that you need about 100 mg/l lime.

Kai