OK. Do not use that algaecide any more. It's adding ammonia to your water which is making it hard for you to get an FC reading. You are fighting yourself. At the top, you said you put in a quart of 60 algaecide. If that was Polyquat, then, while it's a good preventative, it's only so-so at killing algaecide, and also makes it tough to get an FC reading (but it's more benign than ammonia).

With all the di-chlor ("shock") and the tri-chlor tabs, your CYA reading is very necessary, considering you added CYA as well. If it's gone too high you'll have to use only bleach/LC or Cal-Hypo (assuming your calcium level is low).

Carl