Why does this happen?
You don't need to replace the bio media. Only the fine filter pad (white). You can simply rinse out the blue one and replace the carbon one (if you're using it)
I don't have a carbon filter in there currently, what are the notable benefits of using a carbon pad?
I'm going to follow this for cleaning:
I'm thinking I'm overdue as it's been a year. going to tear it down soon and clean it out but I think I've gotta order some replacement media first. Rex is recommending replacing half of the ehfi Substrat bio media. Is this standard practice?