I think they're both 25.

Fortel used to make one that was 10 that you could get at Woolworths but I think they've stopped making it. Otherwise you can get more sensitive ones online.

If the spotting you're seeing is implantation bleeding you'll need to give it about 3-5 days before a sensitive test will pick up a positive...I had IB with my DS and got a very faint bfp on a fortel test about 4 days later.

Good luck I hope you get a bfp for Christmas!