Yeah, I believe there are other companies out there making commerical salt juices in DTL concentrations.
Go to breazy.com, select nic salts, and just flip through the pages. It will show both high and low concentrations, but I believe they offer a number of low concentration options if you aren't willing to DIY or dilute your own.
You don't have to buy there, but you may see some brands that offer salts in a concentration you want.