Yep - it is the sodium. Most of our western diet sodium comes in the form of salt. Most food labels use sodium - and that is what I check. Not salt specifically - though if labels include salt content that would be something to check. Also watch for MSG - another source.
After 4 days my BP has fallen from about 150/95 to just 117/72 this morning.
I have downloaded an Excel template to track it also, and will keep in minimized on my desktop for quick reports. The template makes it easy to see a graph to see visually how your pressure is trending.