Pokémon X and Y Playthrough Discussion

So I'm kind of lost with this rng lock thing when breeding.

I have 2 magikarps one holding ES and the other with destiny knot.

I reject 1st egg, save, accept 2nd, hatch it, write down the ivs ( male passes hp/spd/spe, female atk/spatk).

I soft reset then switch the parents to 2 sliggoos having 31 ivs at their respective stat, put dk on male and es on female, get egg, hatch it and the only one passing down the ivs is the male.

What am I doing wrong? D:


Edit: I got this, both magikarps and replace parents had ev's and effed up the baby.