i've had over a dozen big blues on my one before a blue swam away with it,, i figure money well spent. but we do put leaders on them now, and it still produces. hope you got the silver with blue back thats the hot one with the most strikes.
trick i tried today that i read somewhere, can't remember where. to get those 25's even deeper use with a trolling sinker (i used a 4oz) about 6ft infront of the lure. deploy it while not moving, when it hits bottom bump motor into gear and let out line as you get upto trolling speed. seemed to work, when we stoped to bring in a big blue the lure was bouncing off the bottom as it was reeled in.
hottest trolling speed i found, for blues anyway, is about 3mph water speed.