It's the SanFran strain that makes for the size at hatch, the platimum grade of SanFran isn't any smaller at hatch than the lower grades of SanFran. Only difference is guarantied hatch rate

I used to run a research lab that would go through a case and half of cysts per week at the height of things. Those volumes do make the platinum grade cost effective, but a good quality non platinum works just as well for the fish themselves. I started using the SanFran from Brine Shrimp Direct several years back when Platinum grade wasn't available due a couple of poor harvest years, they work just well, just a somewhat lower hatch rate. Also found I like dealing with Brine Shrimp Direct better than Argent, better service from the sales department.