Secret behind keeping aggro as tank?

Whats up guys, tank with gs 3,7k here. Never had problems keeping aggro in one star dungeons. In two star dungeons however, somtimes melee dps player (gs / dagger) overtake aggro and cause chaos obviously.

Is there any secret behind keeping aggro? I got 3 aggro spells (chain / scream / gs aoe) and I feel like this might not be enough. Do I need 5-6 aggro spells all fully maxed out to keep aggro? or do I rather need 4k gs? What do you guys think :D