I found cal-hypo in the form of HTH. It looks like HTH shock comes in 1 pound bags (around 60% chlorine). Using bleachcalc it says that I need to use 0.4 gallon of 6% bleach to raise chorline 1 ppm. How much HTH does that equate to?

Also, can I use HTH tablets in the skimmer as a way to maintain the pool when I travel for 4 or 5 days?