On the negative side, limewater does have some concerns that don’t apply to most other systems. One is the effect of overdosing. All calcium and alkalinity additives, if added in sufficient overdose, can case abiotic precipitation of calcium carbonate in the tank. Limewater, however, is especially prone to this effect for two reasons. If overdosed, the high pH of the limewater will rapidly convert much of the bicarbonate in the tank to carbonate, increasing the likelihood of precipitating calcium carbonate. Also, addition of solid lime particles can cause local extreme spikes in pH and calcium that nucleate precipitation of calcium carbonate. Consequently, limewater overdose, especially dosing of lime solids, is by far the most frequent cause of “snowstorm” events where calcium carbonate precipitates out all through the water column. In some cases, the tank can look like milk. The good news is that this event rarely causes lasting harm to tank inhabitants (at least that has been recorded to date), but it is nearly always upsetting to the aquarist