The answer depends on your CH level.
If you are at the low end of the recommended range of 250-350, then use the cal-hypo. It is way easier to get the required FC into the pool. I find that it does float and when sucked into the skimmer socks does seem to degrade them a bit faster, so if you have socks on, you might take them off.
Now, how you KNOW your CH is important. Your own testing is best. Test strips are useless and pool store testing is always suspect; believe them only if they are consistent and reflect the changes you know have occurred in your pool.
Otherwise, given your volume Liquid Shock from a pool store would be second choice. You may find 10% or 12% locally. Or bleach, 3 packs from Sam's or grocery store house brand. Gonna take a lot of bottles to get you to shock level, stock up as it may take a few days to burn out anything that has started growing.
You will need to do a full, proper shock, not just hit the shock FC once and then done.