Very Confused - Cichlids vs. Brackish Water

Note that I'm not saying that I agree with my LFS recommendation!

I'm just passing along the message, and I attempted to convey my doubt in my post, but seem to have failed in that regard.

I have crushed coral in my malawi tank, and they seem fine for now; pH is around 7.8 or so. My GBR tank is at 6.6, so it's sort of funny having both extremes (not that either is extreme really)
 
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