If they don't like filters...

[ramble]

I hadn't found a Whisper one I thought would work - 1, because my water level is low right now, about 2/3 filled (I started at 1/2 have been raising it about 1" each water change) and 2, I have had two for my other tank break this year (crappy hangers and suction cups) and I'm not too terribly happy with that brand right now.

If I don't find anything else that will seem to work, I can go that route though so it's good to know the amount of flow is right.

[Jenste]

you could also try an elite stingray internal filter, just aim the output at a corner. I have used this with newly morphed ACF froglets with success