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The flocculator was originally made of soft flexible clear tubing. The tubing was pinched as coiled along the flocculator. Additionally, the tubing degraded at the joints (See Figure 1). 
Figure 1: Deformed and pinched tubing. (12/13/08)
figure:....................) Air leaked into the tube at each of the bulkhead fittings. This air prevented flow through the flocculator. The plant operators advised using a thicker, more resistant tubing to solve the problem of degradation.
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Air often gets caught in the connection between the 1/4 line drawing water from the tank. To resolve this issue the peristaltice pump used to sample water from the sed tanks was used to provide pressure to remove air. Additionally the joint was sealed with tape to make it air tight (Figure 2). 
Figure 2: Sealed air tight . FIGURE >>>>>joint. (12/14/08)
For additional information on flocculator issues see Flocculator Maintenance