I’ve had some organic potting mixes that were too acidic. To counter act and stabilize ph in your pot whatever you use, add 1/4-1/2 cup of dolomite lime, 1/4-1/2 cup azomite and you can use oyster shell powder. That’s what I did this year and it has worked very well. I do little to no ph testing and use filtered tap water and it’s the best grow I’ve done. Those soil amendments really do stabilize ph in your medium. Good luck brother.