If it cost no aetherflow it will become part of our singletarget dps rotatio and you need try find situations once all your 3 dots have really small duration left. Other words You need "sacrifice" your singletarget dps if you hold your tri-disaster for the add mechanic that is gonna spawn later. Thats why I prefer aetherflow system myself. I like the idea you should use tri disaster only if your opponent is clean of dots and you can choose when you use it and not every time it is out from the cd.