I was so confused recently, I made a batch of soil for my container garden. Here what I added.
3 gallon of pine bark
1/2 gallon of peat
1 gallon of perlite
3 handful of Turface MVP
2 handful of worm casting
2 pinches of bone meal (I have middle sized finger, about 1/4 handful)

mix them together really well, then water again. Catch the leache, you know what the EC value is about 2000us/CM, what's wrong with me. There is no lime or gypsum whatsoever(I added gypsum in another batch, and the EC value is over 3000us/CM). Where is the ion from? I mixed the worm casting with water, the EC is about 450us/CM. I have really good quality water, the EC is about 150us/CM.

What I have been doing for so long was wrong?

Whoever has a EC/TDS meter, please help.

I am confused!

Tao

I keep flushing my pot for about 10 times, finally the EC value drops to about 500us/CM.

That keeps me thinking that after making the fresh soil mix, maybe we should flush the mix really well with clean water until the EC value drops to a reasonable range. There is a possibility that for slight acid mix like mine, once you add lime or gypsum or even bone meal, there is a reaction to release the Ca+ ion. If you don't flush the mix well with water, the EC value going to be very high initially. The value is only going down after about 10 deep watering. Unfortunately most of the time when we transplant, we just water once until the water runs out from the drain, the shocked plant will stay in high EC value soil medium, the water intake is restricted, we water less often, the poor plant will stay in such soil for a very long time. That may explains that why so many new transplants get stunned growth for such a long time.

I am also thinking that the micro-nutrients and all other organic supplements should be mixed after the flush.

Thanks
Tao