Liquid Nail is a glue, and Liquid Iron is a spray that you applies to clothing so it will remain winkle-free.... <jk>
Seriously, some macroalgae have higher-than-NSW concentration of iron, and so as a marketing ploy, they come up with a iron supplement that is slightly better than a rusting-nail-in-the-sump thingie that suppose to help with these issue.
Sorry for being so cynical, but IMO, if you can't test the ionic concentration, and don't understand why you tank needs it, it is better to stick with regular water change instead of dosing this and dosing that.