Since I have had my Protank II the only thing that would have given me a burning taste would be when I rebuild the tank and I mash too much wick into the Atomizer Coil head. I am not sure of what you are doing, but this is what I do:
- typically when I get a gurgle before the tank reaches half full, and I had just put a rebuilt coil in there then I will removed some of the wicking material
- if I get a burnt hit after I just put in a freshly rebuilt coil, I remove some wicking material.
- if I get burnt tasting after couple of tanks, i take the Protank base, pop open the atomizer head, remove the wicking material and give it a pulse until the coil gets red hot. As the coil is cooling down I blow on it to remove the residue off the coil. I then take a q tip and wet it with a little e juice and use this to clean the coil. The wicking material that I removed, I will throw away and re insert new wick. if i still get a burnt taste after this, then it is time for me to rebuild the coils.
- it could be a brand new coil head or an old one, but I will ALWAYS rebuild it. I use either 28, 30, 32 gauge Kanthal A1 built to anywhere between 1.5 Ohms to 2.5 Ohms, and Cotton.
- for 100% VG i put enough wicking material in there to cover the holes at the sides of the head, but just enough to keep the cotton fluffly. If when install the head on the protank base I notice that there is a gap, a fluff up the cotton with one of my wifes sewing needles until the gaps are covered.
- for PG and PG mixes I will do the same thing except I put a Flavor wick, and instead of fluffy Cotton i try to slighty roll and compress the cotton
Thing that I noticed is that many people would try to stuff too much wick in the atomizer head to try and stop the gurgling. It may stop the gurgling up until a certain point, but everything before that point will be a burnt hit, or a 1 - 3 mouth-to-lung drag (or 1 long Lung drag) before a burnt hit.
The gurgling with the Protank is another thread on its own.... but just through trial and (A LOT) of error I found what works for me. I have fired the protank all the way up to 20 Watts on a friends DNA 20 Mod. For me anything past 16 Watts is where I start tasting burnt stuff.
Oh yeah I also kinda modified my ProTank not sure if this could also be the cause of not getting burnt hit, but the buddy that had a DNA 20 mod has a unmodded ProTank with no complaints, so I am not too sure about it. But the holes at the base of my Protank (the part that screws on to the 510 Connector) are drilled out to a 1/16 Drill Bit (since I like taking lung hits). The additional airflow could be helping cool the coil.