yet another thc urine analysis "am i gonna pass" thread...

so here's my situation...

i am in my early thirties, very fit (body fat around 10%), exercise a lot, and have smoked 4-5 times in the last month, the most recent being this past sunday (7/16). my UA is this friday (7/21).

as an expirament today, i drank a piss load of water (pun intended) and took an at home THC 50ng/ml test and it came back negative (with a very faint pink line, per the test this is to be considered a negative).

i have read here that lab administered drug tests are no different than the at home variety in that the initial screening is done with an identical test to the home test and only goes to more thorough testing if the initial screening fails. so i guess i'm looking for confirmation that this is the case. i have bought two different same day detox products (qcarbo plus and detoxify xxxtra clean) that are taken 2-3 hours before the test. should i take these just to be safe, or is this unecessary and possibly risky in that something in them will show up in the test as a red flag?

appreciate any help/advice.

I would just drink more water and take a chance not using the pills, you never know they might show up and you fail because of deception.