10 Gallon Tank High PH in ten gallon planted tank

Just did a ph test two days after a 30% water change, and my ph was super high in my ten gallon. at least 9.0. Immediately did a 50% water change.my tap water is 7.0 so it can’t be that. My betta fish is doing fine, no signs of illness. I think it’s possible that because i have sooooo many plants (tons of floaters, dwarf sag, a medium sized crypt, a few small java ferns, ludwigia, pennywort, four anubias, and a trident fern) they might have been sucking up all the carbon dioxide and in turn making my ph super high? Idk. How can I keep this from happening again? I have a lot of almond leaves in my tank, but they clearly aren’t lowering ph. I took out a handful of floaters but there’s still a lot, and i love them so i don’t want to get rid of them. how can i combat this?

 

Are you sure the test is not faulty?

 

Is 7 PH straight out of the tap or after it has sat out overnight?

 

I would test again. Something might have been in the tube to contaminate the test and give a high ph reading.
How long has the tank been set up?

 

As mentioned, test your tap water immediately, then let it sit overnight and test again.