segrid, Welcome to the forum!
It will take some time for the alk to drop ( I think your drop to date is good, given your ~large pool). I know you want it to be 'right' right now, but patience and perserverance will do you better than any 'quick - fix'. As long as you don't have an immediate problem concerning the alk level, doing the lowering slowly will prevent future problems.

Congratulations! You have decided to 'take control' of your pool, rather than just getting 'someone else' to fix the issue! You have done 2 good things; i.e. taking your pool into your own hands and comming here to learn 'how to do it properly'. Should you ever need help with anything, feel free to ask me or post (the folks here are the GREATEST!!).

Once you've taken care of this 'temporary problem', if you follow the advice here you shouldn't have any more problems !!