Are there any cheaper sources for pool chlorine or Tri-Chlor tablets
then the local Home Depot? Or if not Tri-Chlor tablets, is there any
cheaper way to stabilize chlorine levels? Thanks.

pelty writes:

Are there any cheaper sources for pool chlorine or Tri-Chlor tablets
then the local Home Depot?

I say we all go in together and buy a container load from China. Less than
$1/kg.

See if your local pro supplier will sell you a 50 kg drum.

What's the shelf life of granulated Cal Hypo by the way?

Paul Giroux writes:

What's the shelf life of granulated Cal Hypo by the way?

Cool and dry, must be years.