Of course. How silly of us to guess that there could possibly be calcium carbonate in the substrate by say using white aragonite rather than something inert. Or that the tap water could be 8.0 and kill some species of shrimp. Maybe a rock that was leeching minerals into the water. No, of course not, they're using pure RO; that's the only thing that could be causing the problem and pure tap is the obviously the best solution, all variables aside.