Hopefully...minor clarity issue

[Watermom]

In an 18K pool, each pound of CYA should increase the reading by about 7ppm. I think you can add 1 to 1-1/2 lbs to start with. Wait a week to make sure it is dissolved and then retest and then you can decide if you need to add more.

Regarding your alk, you can add some baking soda to bump it up some. Add a couple of lbs. at a time. Gradually increase your alk to somewhere between 80-110 or so.

[madwil]

I can understand your concerns on CYA, but anywhere in the 30-50 range should be much more manageable...
You can add the CYA in stages, add half, retest next week, then add the other half if still needed!
the alk boost will help over time, just don't overdo it...