I have to be totally honest. I had a super hard time with ovulation tests. Mine were all over the place with results. The only way I knew when I ovulated was from temp taking. It's useful in a way and also not since it tells you that you JUST ovulated which is often too late. But if you follow the pattern, it helps you know our ccle better than anything else. I took my temp every morning before I got out of bed and put the number down. My temp would rise a full degree right after I ovulated. It stayed high until my period came and then it dipped back down. Like clockwork . . . except for two times, both times I was pregnant. Your temp stays to the higher degree when pregnant. When I charged this, it helped me it helped me know right around what day of my cycle I usually ovulated on. I had sex every other day about a week before that date and caught the egg.
I did have luck with the monitor. It was different than now, not touch screen but it reads more than the regular ovulation tests. It costs more but think it is worth the expense personally.
I know I wasn't too helpful but wanted to try to answer.