Urine and water halfway through flowering to prevent yellowing at the end? i hear urine has high levels of N from the ammonia.
WRONG!!!.. based on what you said never piss on a plant for the ammonia...
ammonia is NH3 with no charge, therfore it will not bond with the carbon chain of plant matter. NH3 is in it own little happy world where the Nitrogen wont leave his threesome with Hydrogen for some bald fat carbon chain.
put it like this Nitrogen wants 5 dallors for a soda but Nitrogen only has 2 bucks. 3 thirsty Hydrogen walk by the soda machine but they only have 1 dallor each. Nitrogen come up and asks them to pool their money together and buy a soda to share. no longer thirsty the atoms are no longer looking for anyone else with money, so they walk away as a new group of freinds.
in relavence to chemistry
money = valance electrons
thirst = enthalpy "which means the fact that everything in the universe wants to be at a low level of energy, and making bonds lowers energy."
also a tid-bit about nutes
all nutes ill just use the major ones N-P-K have to be broken down into ions"a atom or compound that has either a + or - charge" before they can bond to the plant matter. for soil nutes they use micro-organisims found in soil to break down what you actually pour on your plants.For hydroponic the nutes already come in an ionized form. that is the reason why in hydroponics you have to mix diffrent nutes in a specific order. if you mix ions with a + and - charge before u dilute them in water you get compounds like "ammonia" that do nothing except make your tanks look cloudy or even have soilds in it.
example
if you mix K( potassium) with N(nitrogen) you get the compound NK3
because k has a 1+ charge and N has a 3-
add it up
sorry for the rant i just got out of the lab.