Here's a tidbit from a comparison on RC and ESV I just stumbled across.
Though the person now says they've not seen any evidence to suggest~ (why is that Mr.! :p)
I think anecdotal counts to a fair amount, though not proof imo, I know many on this site consider it to be. What I was referring to you can find more info on, I believe there's research concerning urchins, zebrafish, another fish I can't recall atm, and then frogs as well. Though as you'll discover (if you care to look) the other fish did not exhibit the same effects as the zebrafish with problems developing.
Though I agree as an average you'll not find lithium levels high enough to cause a lot of the issues, it's still a valid point when comparing salts. (I believe the topic is Best salt mixes?)
Please don't QQ me, I'm only trying to add to our repository of knowledge, and though I am familiar with the AA verdict, there's been much more research into the effects, so no matter what, at the very least, you cannot say it doesn't affect organisms, period. (that's definitely cheapening the wisdom of the hobby and the human race) As to what extent, that's debatable, but don't let others fool you into thinking it's established that it's known. Even 'not seeing data' only proves one thing, there's been no conclusive facts. So it could still be a true or false.
I do not know what effects lithium has in a reef, but it is biologically active. Craig Bingman tested mixes years ago and found most were elevated (like Reef Crystals is in your test), and Coralife was very high (and IIRC, a few people associated that very level with problems)
Aquarium Frontiers Feature
Picking between these two only, and assuming the data is accurate, I'd elect the Reef Crystals because of the elevated lithium and lead in the ESV.