I can no longer in good conscience recommend Leucidal liquid as a preservative. It is failing challenge testing all over the place, and it appears from this study that the only preserving power it has is thanks to the preservatives put into it. (Please read this study to see more about this...)
I am sure some of you out there are using it and finding that your products aren't going bad. I'm sure there are companies in the same position. But considering how many people are having problems with it - including huge companies like Badger - and considering all the things that could inactivate it - for instance, not getting the pH in just the right range - I do not feel comfortable in suggesting this for anyone who is making products at home.
If you want to use Leucidal, then have at it. In the end, all I can do is suggest that you do your own reading. I definitely recommend you ddd something to it to make it a broad spectrum preservative, like potassium sorbate. Please remember that my goal here is to offer the best evidence based information I can, and right now, the evidence I'm seeing, hearing, and reading for this one isn't good.
References for further reading:
Making Skincare - do a quick "find" on the page or just scroll down to read more.
Identification of Didecyldimethylammonium Salts and Salicylic Acid as Antimicrobial Compounds in Commercial Fermented Radish Kimchi
Badger sunscreen recall
Anne-Marie of Soap Queen's comment. (Do a find for "Leucidal" to find her comments)