Confused on which day I ovulated..

Jamie • Ttc baby #1. 09/03/20 👼 Happily married to my best friend. 02/17/15

Please excuse me but it has been some years since I last temped. I am using Glow and Fertility Friend and Glow says I ovulated on April 10th and FF says April 9th. Also Glow doesn't have a cover line but FF does how come? Thank You for your input.