I am really having issues with OPK's this month

[Ley]

currently on cd24, have been using OPK's for 2 weeks. Testing twice a day.
I was using IC's but got bored of seeing the same faint lines every day so 3 days ago I bought some tesco ones.
I got a positive straight away on those. Later that day i got another pos on the tesco ones and tested an IC with the same urine sample but got a barely visible line.
Now 3 days later I am still getting strong positives on the tesco ones and hardly anything on IC's. I know you are supposed to stop testing after your positive but I was trying to guess my ovulation day so was waiting for the line to go faint to work it out.
Anyone have any ideas whats going on? Did I ovulate or are the tests just being weird?

 

[Ley]

anyone?

 

[aussiettc]

can you post some picks of the tests?

 

[nmariern]

It's hard to tell with out seeing the tests. I also think using two different brands would be confusing too. How many days are your cycles normally?