I assume you mean you're dividing with a solid wall and not something with holes to let water pass?
best thing I would think would be small, tiny, sponge filters turned down to just barely functioning level. but if you are trying to get them ready to breed then I have no idea because they won't like the sponge filters very much to make a nest.
best thing I would think would be small, tiny, sponge filters turned down to just barely functioning level. but if you are trying to get them ready to breed then I have no idea because they won't like the sponge filters very much to make a nest.