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As was observed in the Carbonate Settling Observations laboratory, more precipitate can form after a concentrated solution of Ca(ClO)2 is diluted with non-distilled water as the result of the calcium's interaction with CO2 (Equation 1). Precipitate could also form as a result of its interaction with other chemical species located in the dilution water.
We have now come to the conclusion that if the majority of the precipitant is removed from settling, the only other way that the flow will be impeded will be as a result of Ca(ClO)2 solution coming into contact with the atmosphere. Locations where this could happen are at the surface of the stock tank that holds the Ca(ClO)2 solution, the surface of the constant head bottle where the float valve is located, and the orifice located in the float valve where the solution is forced into the constant head bottle (Figure 2). Insert pic

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As was examined in the Final Restriction of Flow of Hypochlorinators experiment, if there is a solid material present like plastic or metal when the Ca(ClO)2 solution comes into contact with the atmosphere, the precipitate will form on the surface of the plastic or metal (Figure 3).
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If precipitation forms in the stock tank or at the surface of the constant head bottle over time after the initial settlement, it would flow out of the tanks with the rest of solution or settle out at the bottom of the containers, as was observed in the Final Restriction of Flow of Hypochlorinators experiment. If it continued through the system with the flow of solution we are confident that this small amount of precipitate would not build up, or impede flow at any point in the system. This leaves us with the float valve orifice. Every instance where we were able to restrict flow from the orifice in the float valve there was a buildup of precipitate all over the surface of the float and the arm holding the float to the rest of the valve. It appears that precipitate is slowly forming in the orifice where the solution first comes into contact with the atmosphere after leaving the tube that flows from the stock tank, eventually restricting flow (Figure 4).

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