The crustiness of low calcium is caused by excess magnesium locking out nitrogen.
Every molecule of excess magnesium locks 1 molecule of nitrogen. I don't think low calcium is your immediate problem as other than the tips the plant looks really healthy. I tell you about excess magnesium (low calcium) so you know what to watch for if you dial the calmag back.
As soon as the plant looks a wee bit light in color, check the soil for crustiness. You should be able to easily stick a finger in anywhere, even around the pot edges. As long as the soil is fluffy your good.
If its just starting to get crusty, time for a weak dose of calmag and some EWC across the whole top of the pot just barely deep enough to cover. Don't choke the surface with EWC. Lighter layers more often work way better.
If you ever topdress a mineral mix, like bat guano or whatever, putting it on and the ewc right over top of it works really well.
I poke fingers into my pots every day. Caking is different. Caking just under the surface can be gently broken up, its just EWC clumping up before it really starts to work. The crusty stuff that didn't appear after using EWC, thats the calcium isdue. 1st watering after EWC has been topdressed you usually see crustiness, but again thats EWC starting to work so crumble it, but its not a calcium issue.
If you haven't topdressed for a few waterings and things go crusty, thats a calcium issue.
So here is some logic on that, as calcium can be dangerous.
When the soil needs calcium, which is the majority of the calcium issues, and it goes crusty, calmag will fix that ON CONTACT.
Thats important to remember.
It has an electrical charge and tames excess magnesium on contact, so don't mix it too strong.
If a light dose doesn't fix it, you can always do another light dose. Go too strong and plants fry.
A light dose is the weakest mixture from the instructions. Calmag instructions usually have 3 strengths on the mixing instructions.
The light mix is to maintain current levels, or fix minor things. The medium is to fix minor things and feed and maintain, the heavy is to rescue. Try to feed light and maintain but never need a rescue.
If the plant doesn't eat the calcium and it is only being used to condition the soil, which is what most need it for, it can build up and tips start to burn.