For my 240 i have a fluval 403 with sponges for my mechanical attached to the return is an UV light. I use a 50 gallon sump with bioballs and ceramic media for biological filtration
for my 210 right now there is 4 in tank sponge filters, fx5 modded to hold more media that is layered with 10ppi about 3 inches on top, then the original sponge that it came with, then Matrix probably 3-4 liters, then 12 scrubbies at the bottom to prevent the motor from sucking up the matrix.
And a eheim 2217 without the carbon/finer pads.
ac500 with 3 inch 30ppi poret foam with bio max on top.
Soon to be getting another eheim
In both my 404s I have biomax in 2 chambers, while filter floss in the last. The Fx5 has all biomax with an addition of a polishing pad on top of the last chamber for temporary clearing.