Hello,
I have also no problems in a 160l tank, but for breeding I would prefer a smaller one.
Your construction is intresting, but your overflow-system have one problem: the fry. They will be blown in the next tank and you have no control especially when there are different species inside. I wouldn´t use a kaskade I would use da normal tank with “Edelstahlgase oder Edelstahlgewebe”, Maschenweite im µ-Bereich (sorry I don´t know how to say that). That is like an static net which only allowes water to pass. Than it is also so much easier to construct.
Have fun while informing 😉
Bennie
PS: Maybe I will post a tutorial to build tanks by e.g. wood where it is much easier to create individual.