how do you know the strength? what tester to get?

[NRG_injected_CoMeT]

was just wondering if there is a way of knowing how much MD** is in a pill with a testing kit? like, if there's only a small amount will it still show up? also, if there's more than one substance which one will show, will it be the one with the most in there? so for example, say you've got a pill with speed and MD** in it, but it's mostly speed, what will it show up as on a tester?
cheers for the help. i know nothing about testers but want to get one so if anyone can also tell me what is the best one to get it would be appreciated.

 

[mayday]

You cant really test strength with a test kit... The rate of reaction gives a VERY vague and innaccurate indication perhaps, but test kits are only designed to indicate presence of a substance, rather than amount of substance.