ᐅ Microcement appears blotchy after sanding

Hey everyone!
I’m currently working on our concrete stairs using residence Concrete Mineral (slate gray).
So far, I’m satisfied with the application.
However, after the first sanding, the result looks terrible.
It’s completely blotchy.
I’ve attached a photo of the stairs after sanding…
Maybe someone can help me or has an idea how to prevent these stains.
Best regards

You probably won’t be able to avoid variations in color after mechanical processing.
BUT!
Mineral surfaces should definitely be treated with a surface protection.
This could, for example, be a clear sealant based on synthetic resin.
I assume that with surface protection, it is possible to achieve at least a largely visually uniform surface appearance.
Please keep in mind that cement-based materials, including concrete and cement screeds, naturally have different absorption properties in various areas of the surface.
This is due to the material itself.
As a result, slight “cloudy” shading can easily appear.
If you want to completely prevent this, you will probably need to use a pigmented sealant (after prior priming).
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Regards, KlaRa

Did you apply two coats? Since you sanded first, this seems to be the result after the first application.

Did you apply it using a stainless steel trowel? What kind of sanding pads are you using?