im a cable guy and we use the poles in the training yard they are un treated. the poles are in sleeves in the ground and bolted in like a christmas tree stand, but 6 feet deep. i got 7 of them 4- 40 foot 1- 30 foot and 2- 22 foot poles.so ive got the pole to go as high as i need. Are the hps lights pricey and where and how many for a 65 foot round pen, we are gonna do it first then the arena. i was thinking of 3 ploes for the pen to cancel out shadows, but would two work almost as well??