ABC, I have used Aqua Mix products for years and with good results. I would recommend that you call their tech line for advice about which product is best in your situation.
I agree with RC about the slab already having been sealed. I'm surprised that yours isn't. I don't think I've ever gotten a slab for a job that hadn't been sealed by the fabricator. Whether or not they did a good job applying the sealer is another story.
If you don't have access to Aqua Mix products, Miracle in another top-quality brand.
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Kitchen & Bath Renovations (VA USA)