remtom46 writes:

Shock is unstablized chlorine which means it does not have stablizer
and WILL NOT raise the stablizer in your pool
It will however increase your calcium because most shock has an active
ingredient of
Calcium Hypochlorite

That's often the case, but at least here in Florida, *all* the dry
chlorinators are cyanurated (falsely called "stabilized" by marketing
phonies) at stores like Home Depot, Walmart, Lowes, etc. They don't sell
*anything* with cal hypo in it any more. This seems to have had something
to do with Olin getting out of the cal hypo manufacturing business some
years ago.