Thank you. I appreciate all the info.I would not use poret foam as mechanical. You can get filter socks that go well below the 100 micron level I believe, but most folks stick to over 100 micron otherwise you are changing them too often.
I have only used poret foam for a HMF filter. If you want it to stand up by itself, you will have to go with 4in thick poret which is going to be incredibly expensive you are planning on using it as a wall in your diagram. I think it will cost you like $300-350 for just the foam.
Second, poret foam is very dense and holds a ton of water. If you are planning to use as mechanical it is going to be insanely heavy and difficult to clean out a 24in x 24in x 4in block of poret because of how heavy it is. You will not want to be doing this often.
If you really want your tank water to be crystal clear you would be better off going with a smaller micron sock and then changing them very frequently as they will get blocked. I think some folks go with up to 4 large filter socks.
I am really looking for crystal clear water and the idea of having to change out filter socks often due to them clogging quickly with a smaller micron is not something I would prefer if I can avoid it. If I used light diffuser panels as walls separating and holding up 2” sheets of Poret, do you think that could work? I can’t see much online as far as how to setup filters using Poret Foam other than the diagram I posted above.