SCATS

[brackishdude]

Actually, what will happen is when you add LR to a lower SG, the life in there die off & creates a HUGE ammonia/nitrite spike, crashing the entire system. Please don't!

I suppose this is true, using seeded live rock. I guess I was imagining using "dead" live rock, ie not out of another, established marine tank, but dry/sterile. It should utimately become seeded by the brackish tank's bacteria, serving the same general filtration purpose, yes?