Need some help. Being a long time squonker I have got my first tank since the old Protank. If it makes any difference it is an Innokin Ares MTL tank. Got it working great with one caveat. Taste is better when it is 1/2 tank or less and muted some above that. Mixed up some 40PG/60VG and using that because my usual max VG didn't want to keep up and I could taste the first hint of dry hit when chain vaping. That took care of that problem. Is the 1/2 tank and below better taste due to amount of cotton wick going from the chamber out to the tank? I'm out of my usual knowledge zone.
I'l take a shot at this. The biggest difference between a Tank and an RDA is the Vacuum! a Tank is a bit more difficult to get the wicking just right. This happens because it's a sealed unit. With an RDA as long as the wick is wet it's going to vape well. With a tank the wick has to wick up the juice on it's own.
If your tank is wicking better on the bottom half? My guess is your wick is little to tight. The vacuum would be a little less with more air space & this would cause your tank to wick a little better on the bottom half.
Wicking makes all the difference on a Tank! Several attempts have to be made to get it just right for you specific tank

To much (tight) wick & it will mute your flavour, too little wick (loose) & it will usually leak

Some were between these is the Sweet spot
