There are several things to try to produce a more concentrated skimmate.

• Raise the cup slightly.
• Ensure that your salinity is correct, low salinity will rduce the skimmers performance.
• Check the orange air tap is not blocked by blowing it out in reverse.
• Check that the pump is clean and the venturi is not starting to block.

If the skimmer is new, or on a new aquarium, the skimmate may be weak as the skimmer beds in. It is also possible if stocking is still low in the aquarium there may not be much to skim out.