Can't vomit all the water out during Kunjal Kriya

I've tried to do Kunjal Kriya a few times and could not vomit out all the salty water, though I expelled a lot of water. I've been doing 3 liters of salty water 1 teaspoon per liter. I know salty water shouldn't be absorbed by organism, that's when you are doing asanas that propel it through the intestine. But when it is moving slowly it does get absorbed, and I feel swelling in my head afterward and don't feel good.
I've also heard that when you drink the water slowly then there is a chance you wouldn't expel all of it. I think I've drank it fast enough - a cup immediately after cup

I would be appreciate any help