I can understand the notion of the burning taste, that is likely to be little or no eliquid reaching the atomizing coil. But when you say the others have "broke" after 3 weeks what exactly do you mean, are they physically broken? Have they just stopped working? Are they not working efficiently?
It sounds very much like you may not be priming your atomisers correctly.
HOW TO PRIME A TANK ATOMISER1. Insert a full cartridge into your atomiser and attach the battery.
DO NOT PRESS THE BATTERY BUTTON. Draw on the mouthpiece as you would normally, taking two sharp intakes.
2.
DO NOT PRESS THE BATTERY BUTTON. Put the cartridge in your mouth and blow gently and evenly once.
3. The atomiser is now primed, vape as normal.
If you experiencing a burnt taste or limited or no vapour, the atomiser is either dry, or e-liquid is not getting onto the wick, follow the procedure below:
1. Make sure your cartridge contains e-liquid.
2. Make sure the cartridge has been pushed into the atomiser fully so that it sits flush with the atomiser.
3. Insert a full cartridge into your atomiser and attach a charged battery.
4.
DO NOT PRESS THE BATTERY BUTTON. Draw on the cartridge as you would normally, taking two sharp intakes.
5.
DO NOT PRESS THE BATTERY BUTTON. Put the cartridge in your mouth and blow gently and evenly once.
6. Atomiser is now primed, vape as normal.
If the burnt taste persists, it maybe you have burnt the wick due to power being applied to a dry atomiser coil and wick. This often fades with usage, however, if the burnt taste persists, your atomiser may be damaged beyond recovery and requires replacement. Check here for further Tornado Tank maintenance tips:
http://www.totallywicked-eliquid.com/forum/tornado-75/tornado-tank-maintenance-and-troubleshooting-guide/msg197819/#msg197819