Query String URL

I have a client who would like to also have the ability to link to a page with a specific search result – for example, angellfound.wpengine.com/grants-archive/?ajax_search=southern_california. I have it set up in the GA settings and I’ve tried just entering that in the URL, but it just returns the full list. We are using Advanced Custom Fields for the search options (there is no open search box option at this point). Is that possible with this plugin?

Thanks!
Dean