@meduser yes I believe you can use the same pH adjuster drops like you use for an aquarium. Same thing.
Before we talk about soil pH...
What are you using for soil?
It looks to me like you could use some perlite to help your soil remain loose.
So the way you test your soil pH is to just test the runoff water. It's a good idea to do this frequently when you water your plants.
But lots of bagged soils will tell you what the soil pH range is on the bag.
Look forward to your update!