Certo is just another dilution scheme. If you passed after using Certo, then you wouldve passed that same test using just water and vitamins.

And if you failed after using water and vitamins, then you wouldve failed that same test after using Certo.

Why waste time, energy, and money with the nasty-tasting Certo when you can accomplish the same thing using N2's Dilution method?

the problem with substitution is trying to keep the right temperature.
The key to a successful sub is practice. For tips, read N2s Substitution sticky thread, or use the Search feature.