Interesting article on the Debit Spread by John Larson in this month's Futures and Options Trader. http://www.futuresandoptionstrader.com/dhyu75.htm
After a Dec/Feb double top, a steep high volume plunge and a double S1 bottom yesterday TLTs may find support around 82.50 altho July ATMs are only yielding 1% on thin liquidity, so not much interest here yet. Little action in the far months. Look for the hairy bottom.