50 lbs in 22,000 gallons should raise the calcium by more than 100 - this should be visible on the test.

Ben describes a method of dosing cal-Hypo designed to prevent buildup for pools with sand filters. Dosing cal-hypo through the skimmer and letting it dissolve on the sand bed encourages the calcium to precipitate out onto the filter. This acts as a filter aid and can help keep some of the calcium out of solution. I can anecdotally confirm this as I used this method for the last half of last season; I didn't measure an increase in calcium (only tested twice), I did find fine white material (finer than sand) on backwash. Warning! cal-hypo must never be put in the skimmer if there's any chance that any stabilized chlorine could be in the circulation system - this can cause an explosion.