m5eaygeoff It's only a few leaves and not all the leaves with that problem. But it's more than one of my elms that got this problem.

I still seek a answer on this:

The water I use contains a lot of calcium. I have read that it affects the pH value. Perhaps it may be the reason why the tree is unhappy?

What can I do to get the right pH value in the soil, if I have a lot of calcium in the water?
Thanks in advance!

This is not a calcium problem. The tree seems to be happily growing. With calcium issues growth would stall.

the tree is not unhappy, it is growing and if there are only a few leaves there is no real problem. Use rainwater if you can, but as I said before add seaweed with sequestered iron two or three times a year. I agree though with LB, it is not a calcium problem. Cut the leaves off and wait.

Matte wrote: I have a couple of questions that I hope you will answer

I’m not really your man with bonsai, but I’m enough interested in general chemistry, so...

The water I use contains a lot of calcium. I have read that it affects the pH value. Perhaps it may be the reason why the tree is unhappy?

What can I do to get the right pH value in the soil, if I have a lot of calcium in the water?
Thanks in advance!

That’s true. Without rebalancing the dissolved minerals, you cannot set the correct PH.

What you can do:
- Use rainwater
- Use demineralized water
- Use an aquarium water softener for your tap water (it’s safe for the plants)

Your welcome. I hope you’ll find the roots of the problem even if it’s not with minerals now.