Diatomaceous earth for calcium?

[irrka]

HI!
I have a couple of catts that are purpling-blotching-black striping on pseudobulbs: looking Ca+2 deficient by my google-search-diagnosis.

I have a bunch of Diatomaceous Earth i'd bought for different purposes before and that's supposed to be 19% Ca. It's pretty fine ground so i guess would maybe be like a suspension wash? Has anyone tried using it for calcium source? I'd trid gypsum top dressing in the past as well, for the large part kinda washes out and makes a brown mess, but maybe they don't need that much?

Thanks in advance