Tubing and Connector Blockage and Bursting

Burst Tube at Barb Connection

When there is an obstruction in the line, from dried media or biofilm, the peristaltic pumps can produce up to 45 psi of pressure, which is enough to exceed the barbed connector tolerance and burst barb connections. This is clearly undesirable, so if you find that one of your barb connections has burst, check the length of the line for obstructions. If it's an efflux line to the waste container (opaque), assume it has an obstruction.


For the pumps that we typically use for eVOLVER, 1/16" ID tubing does not resist flow in any appreciable amount. If a pump is not pulling liquid, it is likely blocked or obstructed.

Unblocking With Syringe

Biofilm obstructions can happen during long experiments with a biofilm-forming organism like E. coli - your best bet is to pause the experiment and bleach sterilize all lines before restarting. If your line is completely blocked, either replace the line or clear the obstruction by pushing water through the line with a 50 mL syringe (shown below).

Unblocking by Soaking the Lines

If the syringe method does not immediately work to clear the blockage, the blocked lines can be soaked in water for a few days to help rehydrate the dried media/biomass - the silicone tubing is quite permeable, so water can slowly enter the tubing and help loosen any dried blockage so that it can be flushed out with a syringe.

Stuck luer-lok connectors

Residual or leaked media on the ends of luer-lok connectors can dry and leave the connectors stuck. Rather than reach for a pair of plyers, soak the connection in hot water to dissolve the media. This can also help for any stubborn fluidic connection, and make tubing much more pliable.

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