Judy:
Bleach contains 5.25% to 6% Sodium Hypchlorite--that's the chlorine and the rest is "inert ingredients"--which means LITERALLY salt water.

Liquid Chlorine sold in pool stores is EXACTLY the same stuff, but it's usually either 6% (ultra bleach) or 10% or 12.5%. But otherwise the ONLY difference is the label.

Bleach or Liquid Chlorine (LC) is the BEST chlorinator you can use (other than a chlorine generator). It adds NOTHING to your water but chlorine--nothing else can make that claim. It doesn't change your pH at all (Chem_Geek had a great thread on why that is) because its high pH is perfectly offset by the acidity of the chlorine's action.

Tri-chlor tablets adds TONS of stabilizer and is super-acidic--and will lower your pH drastically.
Di-Chlor powder also adds stabilizer and lowers pH as well, not as dramatically as Tri-chlor, but definitely.
Cal-Hypo adds lots of calcium to your water. At some point, it will turn it cloudy. That's the GOOD stuff (68%)
Cheap Cal-Hypo (HTH in WalMart) is 48%. The rest is all kinds of stuff that has to dissolve in your water and adds NOTHING of value.
Salt Water Generators are great but cost Boo-Coo bucks and many owners complain that they raise pH so they must constantly add Muriatic acid.

Only LC has NONE of those problems.

Remember: You got this useless tidbit from a guy who built you a LEAKING pool. You already know he's less than competent.

Al (Poconos) and I rarely disagree, but I have to say you must store that Cal-Hypo VERY carefully--it must stay cool and dry because Cal-Hypo is the most re-active of the chlorine forms. I would much rather get a rebate from the builder, or some pool tools I need (like an auto-cleaner) than a bucket of Cal-Hypo. Al's not wrong--we just have a different perspective. I'm not likely to EVER use Cal-Hypo--I'll use Di-Chlor occasionally when I'd like to see my CYA go up.

But on this we agree : LC is the best chlorine source, whether its says "Ultra Strength Laundry Bleach!" or Liquid Chlorine, or Liquid Shock, as long as it's sodium hypchlorite solution.