Different results from different ovulation tests?

Sarah

I am on month 4 of TTC and caved on getting the Clear Blue Advanced Digital test but have also been using the premom. Clear Blue gave me 4 days of high then a peak. Premom gave me no high or peak. I tested multiple times a day with not too much water drunk beforehand. Anyone have any ideas why they would be different? Every other month I have used premom and gotten a clear spike. Thanks!