I kegged my porter about 2 weeks ago. I put it in my keg orator under 30 psi of beer gas. After a week it was still pouring flat. I gave it another week and it is still not purring the creamy head. I put co2 on it for 2 days at like 20 psi with no improvement. Any ideas? I am still new to the nitro thing. Any tips would be welcomed.