How do you get the missing alkalinity from what was posted though?
You need a water spread sheet that calculates the ion balance. This is the difference between the number of negative (anion) and positive (cation) ions. The ion balance is always 0 but if not all ions are reported or if there are measurement errors the ions may not add up. In my spread sheet I calculate the difference as percentage of the total ion amount. If it's negative cations are missing and if its positive anions are missing. In this case I entered Ca, Mg, Na, Cl, SO4 and then changed alkalinity (or bicarbonate) until the ion balance was 0.
This doesn't work when there are other ions that were not reported. But the only ones that could be present in significant amounts is Potassium (K+) which is fairly rare though. Phosphates and Nitrates, which are other cations we don't usually check for are rare as well. And if they are present in large amounts the water may not be suitable for drinking anyway. This only leaves bicarbonate as ion missing from the list.
In this spreadsheet
the ion balance is shown in the upper right corner.
Similar calculations can be done with total hardness. On average 70% of that hardness is calcium and 30% is magnesium. Which leads to a simple formula for RA if only alkalinity and total hardness are available:
RA = Alkalinity - (total hardness / 4)