Both categories of leaks are likely to occur at some point, and a correction strategy can be prepared.
When a problem will occur can only be anticipated, not predicted.
The resulting mass is frequently low in organic solids (10% to 30% after drying), and the majority of constituents are inorganic particulates from the cooling water that have become incorporated into the microbiological slime.
Even a thin layer of microbiological fouling can be particularly detrimental to heat transfer, as much of the slime mass consists of water, which conducts heat poorly. Scale (mineral crystallization) occurs on heat transfer surfaces under a combination of dissolved mineral concentration and temperature effects.
In both fossil and nuclear plants, if the fouling becomes severe, it will cause the backpressure to rise to its upper limit, forcing a reduction in generated power.
The primary effect is reduced flow to certain tubes, which results in particulate deposition and increased opportunity for microbiological growth.
Additionally, localized high velocities and tube wall erosion can occur as a result.
Scaling of certain common constituents in natural waters (such as calcium carbonate and calcium phosphate) is promoted by elevated temperatures, such as exist on the interior wall of condenser tubes, particularly toward the outlet end.
Other scale-forming minerals (including calcium sulfate) are more likely to form at cooler temperatures.