Water over the 60ml mark in the beaker.

The beaker is filled with aquarium water more than it should be

Once the analysis starts the beaker should be completely emptied, then filled with water that actually comes from the aquarium, when that phase is over it should be filled until the 60ml mark or very close to it. If it is above that level, it is possible that the pump or the Water In or Water Out circuit is failing. If it does not empty completely, the problem is in the Water Out, if it overfills, it is in the Water In.

• Check the lines, it is possible that you have an obstruction
• Check the pumps, make calibration tests to see if the values are constant
• Check the pump heads

It is important to perform the recommended maintenance. Take a look to the maintenance guide. The tubes of the heads can suffer wear and tear, and may  crack.