What happens to LH surge during ovulation? Would the LH detector still give a positive read if u are ovulating?  

Yes it could. An lh surge is triggered when estrogen production from a growing follicle reaches a certain level. Some lh surges go up and down in 1 day. Others can be positive for 3-4 days. Ovulation usually occurs 24-36 hours after the peak so it is possible that the lh surge could still be positive during or after ovulation. Ovulation is triggered by the lh surge but the lh surge is not changed by ovulation.