Sisie,
Y',know, you COULD chlorinate for a while with Tri-Chlor pucks....They'll add CYA and lower your pH. Whenever pH gets below 7.2, start aerating your water to raise it again...the process should bring T/A down into range. Then, when either T/A or CYA is in your target range, stop using the pucks and go back to bleach.

Or you could just add CYA, get it up to your target, then work on lowering T/A separately.