jamesinclair said:
Yes, all my HPs are above 100, but 5 of my pokemon have defense under 100 (80, 83, 83, 84, 96)
Same with speed. I tried to speed up my Camerupt that is only at 67 speed!
I think you're misunderstanding here.
EVs (Effort Values) are hidden points that raise your pokemon's stats over their baseline based on what opponents they've defeated. The idea is that it'll make everybody's pokemon unique (because nobody will fight the exact same pokemon with the exact same team) and pokemon raised by battling will be stronger than those raised by daycare, pokewalker or rare candy.
Basically, you get one or two EVs in each of your stats for every pokemon you defeat (Bidoof gives 1 HP EV, for instance). For every 4 EVs you get in a single stat, you get one point in that stat up to 63 points (252 EVs). You're also capped at 510 EVs total per pokemon (i.e. after they've gotten 510 EVs across all stats, they stop gaining EVs from defeating pokemon)
The items like Calcium, Iron, etc. are basically 10 free EVs in that stat. If your EV in said stat are over 100, then the item won't work.
jamesinclair said:
So the only think I can do is trying to give every type of vitamin to all the pokemon in my party? Theres no quick way to know who it will help and who it wont (like how HMs say able and not able)?
I'm disappointed. What have I been saving my vitamins for if they dont help me against the elite 4? The only one that has been useful is the PP up, and they dont even sell that at the stores.
If I would have used them as soon as I found them, would my pokemon be stronger now or would it have made things easier early on but been the same at the end of the game?
It would have given you a slight edge early on, but it'd all be the same in the end as nearly everyone maxes out their in-game team's EVs at some point.