The filter has 3 baskets, each one being around 2ltrs volume I am guesstimating, actual filter volume being 7.3ltrs. Each basket measures around 200x200x50ish.
I was thinking of running poret in the upper and bottom baskets leaving some ehfisubstrat between them, this way the foam is not a big solid mass and the substrat material should allow the foam to have multiple microbial layers?