Best Filter Media

[Aqua sobriquet]

You can easily cut down the 20ppi blue foams to half height by dampenening them (damp not soaked) and then freezing them for a couple of hours. The frozen foam will stand up to some pressure so now you can cut it with a large and sharp unserrated knife such as a Japanese Yanagiba.

I originally thought that a bread knife might be good to cut filter foam as both substances have a similar internal structure. Unfortunately it seemed to catch teeth at every opportunity. Similarly I did not have good results with trying to use hacksaws or other saws.

How did you find that out?! 😆

 

[Maf 2500]

How did you find that out?! 😆

I honestly can't remember where I heard about it, but I probably saw it on the internet somewhere. I have tested it and it does work on the Oase foams. I cut a blue foam into 3 slices to stop those ball media (Eheim I think?) settling into and blocking all the holes in the Biomaster trays. You have to be careful though, even when frozen, cutting the foam that way is a bit like trying to cut a square loaf of bread when you are down to the last couple of slices!

 

[Aqua sobriquet]

You have to be careful though, even when frozen, cutting the foam that way is a bit like trying to cut a square loaf of bread when you are down to the last couple of slices!

Ha Ha! We often bake our own bread and I sometimes cut it into even slices on my bandsaw. 😆 Maybe after freezing I could do the same with the foam?

Edit: I’ve actually cut circular foams for my Eheim’s on the bandsaw, but it’s easy with a circle cutting jig.

 

[Maf 2500]

Ha Ha! We often bake our own bread and I sometimes cut it into even slices on my bandsaw. 😆 Maybe after freezing I could do the same with the foam?

It might be worth a try. It will depend on the teeth geometry I think, and maybe the speed and sharpness too... The only saws I tried were woodworking handsaws and hacksaws and they just snagged the fibres in the foam, it was a total fail even on the frozen foam.

 

[Aqua sobriquet]

I’ve cut quite a few bits of foam on the bandsaw but not edge on, so to speak. I’m not confident unless I can support the foam on both sides somehow during the cut? I may try knocking up a quick plywood support jig of some sort.