Cal-Hypo is calcium hypochlorite and is very similar to sodium hypochlorite which is bleach or chlorinating liquid except that Cal-Hypo contains calcium so will increase Calcium Hardness (CH). For every 1 ppm Free Chlorine (FC) added by Cal-Hypo, you also increase CH by 0.7 ppm.
Both Cal-Hypo and bleach / chlorinating liquid will increase pH (and TA a little) temporarily, but as the chlorine gets used up, this is an acidic process and the pH (and TA a little) will come back down. There may be more extra base in some Cal-Hypo brands, but mostly it doesn't look like a lot. So really, the main thing to watch when using Cal-Hypo is that in increases CH. Also, note that it doesn't dissolve quickly so should be pre-dissolved before adding it to the pool, especially a vinyl pool, or else it will settle on the bottom and produce high chlorine levels locally until it fully dissolves (above-ground pools also tend to have poor circulation at depths because they usually don't have a floor drain).