You can continue to use the pucks, but they cause your cya level to rise and when it does, if you don't run higher than normal chlorine levels, you end up with algae. That is what happens to a lot of unsuspecting pool owners. Yes, you do need some stabilizer, which is another name for cya, but you have plenty and then some! We recommend a cya level of 30-50. If you drain half your water and then refill, that would put you in the ballpark. If you decide not to do a partial drain, you can live with cya of 100 if you just run high cl levels. See the chart at the following link for more info on cya and cl levels. (Either way, don't use any more pucks as you don't want the cya level in your pool to continue to rise.)

http://www.poolforum.com/pf2/showthread.php?t=365

A calcium hardness reading of 430 is OK, but I wouldn't use any cal-hypo to chlorinate with. Just stick with bleach. It will do a great job and won't add cya.