Hi,
I have MarinePure Biofilter 1.5" Spheres in the back of my Fusion 10.
Should I ever clean this chamber? Or even change the biofilter spheres. I still have lots of unused spheres.
U could stick a turkey baster in there before water changes blow around the gunk. And I never changed mine they been there a year now but I do blow them out once in while. I’m also using filter floss stops solids from getting in my rear chambers helps keep it clean back there. As far as replacing them idk... they will hold your good bacteria so I wouldn’t replace them all at once. If for some reason u needed too I’d only replace a small amount at a time.
Definitely don’t replace them, they are building up good beneficial bacteria. If anything, add more of you can fit them. The more surface area, the better.
As for cleaning, every couple of months I siphon out the water in the back chambers. It’s just to get any detritus that build up back there.