I don't have the answer to this one - too many non educated people who thinks that you can stick anything up in the air and hook up an antenna tuner and it will work or work properly - are just kidding themselves..

Buy yourself a resonant antenna and be done with it.

The antenna I use is a Barker & Williamson BWD 90 Folded dipole.
It works everywhere from 10 - 160 meters - WITHOUT A ANTENNA TUNER.

My other antenna is a off center fed dipole, does everything except 15 meters.
Does not require antenna tuner.

Antenna Tuners or trickers as I call them, does not make the antenna resonant, it just tricks the transmitter into thinking that it is putting it's power into a true 50 ohm load.