Food. Eat man. And don't ditch the protein powders.
Weight gainers have a crapload of calories, but it's only like 7 servings in a tub. Which means you're spending $50 every week or so. They also have a hell of a lot of sodium in them, which as you know, makes you retain water. Hence, weight gain.
Just eat bro. Eat a lot. You'll gain better weight.