I don't know what Champion pool shock is, but I'm guessing it's calcium hypochlorite--Cal-hypo, which tends to push pH up, since your pH is high.

However, if it was di-chlor, that tends to be a bit acidic (which you need) and adds CYA, which you also need.

Is Tranchem a brand of Muriatic Acid? Regular, ordinary Muriatic acid is what you need, not the "green" or fumeless. Personally, I'd fill a 5 gallon bucket with pool water most of the way, add the acid to that (SLOWLY!), and then add that to the pool. Wear gloves, eye protection, long clothes and do NOT breath the fumes!

Can you find out what the Champion stuff is? ("Shock" is misused by pool chem companies to hide the ingredients and make it sound "special". It's a verb meaning to raise your pool's chlorine to high levels, not a noun. What they call "shock" is merely chlorine, usually Cal-Hypo, Di-chlor or extra-strength bleach--"Liquid Shock")