Personally, I would go with a smaller dose, something like 0.5-1.0 ppm, which should be high enough to measure accurately with a hobbyist kit. Extra ammonia isn't going to accomplish much, but it won't hurt much either at 2.0 ppm.
I don't know whether the bacteria actually will help produce a filter on the rock, but it might. It should be able to consume ammonia, but that's different from seeding the rock.
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Jonathan Bertoni
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