Says they're useful for when the power is out – that they're a form of aeration.
If your power is out, then you'll definitely have trouble with anemones.
If your power is NOT out and presuming you use a protein skimmer for aeration, it seems like this device should be superfluous. Can you remove it? Then you'll know if it was related to the problem if the probem leaves with the device.
Otherwise, there are basics to consider first such as age of tank, current test parameters (especially nutrients and lighting), as well as any particulars about any specific anemones in question such as how old, what kind and how similar their old tank was, etc.