Im using eleaf ec tc nickel coils. Temp is set to 600f hardly getting any vapor. This usually happens after I change a coil. after about 2 days of vaping the temp and vapor production randomly changes after only 1 hit and i get full vapor production and a warm vapor until the coil expires in about a week. Im using 70vg 30pg eliquid and the melo 3 mini tank. after the vapor production starts I turn it down to about 500f.