redearslider.com

A lot of you guys are probably using canister filters these days. They all use some kind of glass/rock mechanism to harvest the beneficial bacteria. I have an eheim and their website states you should change 2/3 of the stuff (Efisubstrat) every 6 months. I guess you dont change it all at once so the beneficial bacteria survive...The reason I ask is that a lot of people say the stuff lasts forever and I am inclined to believe them . The stuff is just porous glass that provides a medium for bacteria to grow in. I have the ole "slick on the surface" problem now which i can't get rid of. Its got to be the bacteria rocks. Ive changed/cleaned everything else. Anybody else change theyre media.....

I have ceramic rings for bacteria colonization. One brand says to replace every 6 months, another said to never replace it. My opinion is that any media made for beneficial bacteria does not need to be replaced, only occasionally rinsed with tank water.

I haven't had any problems with the water surface with my filters. Are you rinsing your media and is there sufficient surface agitation?

I've never replaced the bio-media (rings and stars) in my XP3 (it's been almost two years), I just rinse them in the tank water. But, when/if the water surface starts looking "slick," I know it's time for a good filter cleaning (and carbon change if I'm using it).

That Eheim media is supposed to be good...