Spoke tension is way off but wheel is true, How do I fix this
For reference, I used to work for Velomax Wheels, and Easton Wheels.

You may want to back all of the spokes off an equal amount, say 5 or 10 turns.  This will give you a little bit of room for adjustment, without having to completely detention the entire wheel.

There is a book called "the Bicycle Wheel", by Jobst Brandt, that does a great job of walking you through the process of truing.

Another way to tell if the spokes are of equal tension is to pluck them like guitar strings.  Since they are all of the same length and same thickness, equal tone means equal tension.  (We used to attach an electronic "pick up" to our truing stands, and wear headphones so we could better hear the differences when we plucked the spokes.  This shouldn't be necessary say, in your garage where there is a lot less ambient noise.)

A couple tips for truing (though you may know these already):
- Be sure to back off any adjustment that you make on a singular nipple. This will eliminate any possible spoke 'wind-up" caused by the twisting of the nipple.  (example - if you want to make a 1/4 turn adjustment, turn the nipple a 1/2 turn and then back off 1/4.)
- Be sure to give adjacent spokes a soft squeeze to help the spokes and nipples settle.
- check for cracked nipples and cracks at or near holes in rims.

Once it is true, then you can bring all spokes back up to tension (the 5 or 10 turns that you originally made.)

Truing stands are very helpful in holding the wheel in the right position to make your adjustments.  (Rather than trying to do it in your hands or in the bicycle frame/fork.)  they also typically have a measurement pin or finger that helps show where (and to what degree) the wheel is out of true. 

Tensiometers are okay devices.  Here are a couple of their downfalls: 1-no two are the same and they come out of calibration quite easily. 2-several factors, such as how you hold the tensio on the spoke and where you place the tensio on the spoke, influence the gauge reading.

Hope this helps.