Additives will not work on instant-type tests because additives require 90 minutes to fully destroy the toxins. Plus there are too many instructions that must be followed in order to be effective. Most additives require 60-90ml of sample and there are not too many testing places that'll ask for more than 60ml (for example, DOT requires only 45ml for testing). If the additive is added to less than 60ml, the sample gets flagged as "adulterated" due to high chromates or an abnormal ph.

You should use the synthetic urine or a clean substituted sample instead. You don't have to worry about following a bunch of instructions as you would with the additive. Subbing is much more easier than fumbling around with additive vials in the bathroom stall. Plus subbing will work on all types of drug tests, whether its an instant screen, or lab test.

Its so simple, a caveman can do it.

If you are brave enough to sneak in an additive, then you certainly are brave enough to sneak in a substituted sample.