The 100/300 are cutoff limits for THC and an off-topic drug that cannot be discussed in this forum. ostreadrulez:

The NIT code means they will be checking for excessive nitrites as well as specific gravity, pH, and creatinine since they are all part of the validity test.
Nitrites are found in some drop-in addtives used for spiking a urine sample. It is also found in such foods as pork and poultry. The human body can also produce nitrites naturally, though this is a sign of a urinary tract infection. For this reason, only a tiny amount of nitrites can be permitted in a urine sample.
Under current DHHS regulations, any urine sample with a nitrites level over 500 mcg/ml (micrograms per milliliter) is considered "forensically defensible" as proof of adulteration.

All magic detox drink potions are an overpriced way of accomplishing the same thing that can be accomplished by following the guidelines outlined in the Dilution thread.
Because the drinks work by dilution, the urine sample would not be flagged for adulteration, but would be flagged as "overdiluted" due to the creatinine and specific gravity being too low.

And because they work by dilution, detox potions (like any dilution technique) can backfire if the THCA concentration in the bladder is too high. For most daily users, its virtually impossible to dilute that concentration without overdiluting and sending up the red flags at the lab.