I am new to vaping and I have an evod pro tank and battery. The e juice I use is either a 50/50 blend or 60/40 PG/VG blend. The nic level is 18 or below. Every flavor I hit as soon as I inhale I start an instant cough. I have inhaled many different ways as suggested on this forum. The only e liquid that does not do that is a chocolate blueberry and smooth menthol mix. Btw I have smoked menthols for 15 years. Any advice. Thanks.
First off, welcome to the ECF, hope you enjoy the stay!
Now, on to the meat of the topic....
What liquids ARE causing it? Where did you purchase them?
One thing to be aware of coming off the cigs, is that there are analgesics in cigarette smoke that cause a minor numbing of the throat/ nasal passages as well as the cillia in your lungs. Coughing after switching isn't all that uncommon. It could be as simple as this. It shouldn't last for too long though, if its still causing coughing in a few days with no change whatsoever, best to look at the other potential causes.
Could be that any number of things, really. So far all the posters here have suggested the number one cause of the coughing issues, perhaps the biggest being too deep of a drag... don't try "lung hits" (direct lung inhale) off the bat, because those will certainly knock you off your feet until you're used to them.
Try a "lighter" nicotine percentage, its possible that the 18mg stuff is too harsh to you.
It could be a PG allergy, but that is unlikely... its a very rare thing to have. But, in the interest of seeing what's causing it, trying a 100% VG juice would at least rule that out.
The flavors you mentioned sound rather smooth, so maybe its the flavors of the juice being too strong as well... I know if I hit one of my DIY's right after I've mixed it (I always drip a few drops to test it), it will be harsh and kick me in the chest a bit.
Its also simply possible due to the looser draw of a protank you're taking a much bigger hit than you think. Try the light draws and see if it helps at all.
That's about all I can come up with right now that might be causing the issues, hopefully one of us nailed it so we can help fix it.