My new bonsai kit is arriving today. I went with the Planter’s Choice 4 tree starter kit (hope this is a good one).
In my opinion, it's not. You're just buying ordinary, but overprized, tree-seeds.
Don't use a water gauge. It won't work.
If I'm right, no one of the regulars here uses grow lights. We grow our trees outdoors, where they belong.
I have never ever used a PH gauge.