Wow, there is a nice expression how circulated tanks can be.
As I already wrote I am also trying a little pump. The circulation is very soft, becouse I used the smallest one I can find (actually for nano or shrimp tanks) and lead it into swimming plants. So there is a circulated part and a still standing one.
The Parosphromenus seem to be in both parts but the linkei is more there than the sumatranus, wether they swim sometimes still standing in the foat.