I am using the aspire K3 vape pen, and the Nautilus A10 replacement atomizer. So far I've been happy, but this last pack of replacement atomizers are bad. Normally, an atomizer will last me about 5-7 days before I get that cottony taste. However, with this pack, I loose all flavor after the 2nd or 3rd refil, and after about 3 days, my juice starts to turn black within a couple of hours after refil. Have you changed the quality of cotton inside the atomizer? I have not changed juice, nor anything else in my vaping routine? Do you have an explanation for this?