Cultivation and Contradiction

I have had 2 somewhat successful grows in the past...somewhat meaning i got the plants to finish but yield and potency were not satisfactory...I dont understand what im doing wrong...i get the lights down,as well as ventilation and room cleanliness (IE never had problems with mold of insects) yet there are 2 main parts i have issues with and they must be either water or nutrients....I have only ever used NSR green leaves grow juice and bloom juice...no extra enhancers amino acids or bloom boosters or extra ferts...nor have i ever PH'ed my water...ive only ever grown in soil. i was looking at a new set of nutrients advertised in High Times put out by Advanced Nutrients which are whole sets of nutes organized by hobbyist,pro,and expert...they also state that the PH is pre set and therefore you never have to adjust it what would be the difference from hobbyist to expert? would the expert nutes be more difficult to use? what makes a expert grower? also is all the other added bloom boosters and shit needed? also on my last grow as you can see from my old threads i had one plant out of 2 begin forming insane amounts of necrotic patches on the large fan leaves...the budding process virtually stopped i never could find any sign of insects or anything how would i tell if the symptoms were over nuting or under nuting considering i treated both plants exactly the same and only one was injured....also i have always put the same amount of grow nutes in the water through the whole vegging cycle but looking at a more complicated growth schedule i noticed some people put more or less nutes as well as different nutes all together for different stages of the plants growth cycle is this neccisary or preferred? should i be putting different amounts of nutes for different stages? should i get a more marijuana-specific nute? as i said i only ever use simply NSR grow juice or bloom juice it says it contains micro nutrients as well as the basic the grows juices NPK is 2-1-3 and the bloom is 2-5-4 sound right? ive been typically using 1/4th the reccomeded strength every 3rd watering with my grows...i nearly always either have some patches on my leaves or necrotic leave tips i get them to bud but its never as fat or sticky as i would like ANY HELP APPRECIATED

I know this may not sound helpful but what kind of soil are you using? Depending on what the soil has in it and how it was made may slow down growth.

for vegging you want something like 20 10 10
and for flowering you want something like 5 20 5
if anything i said here helped you dont for get to +Rep