Bioballs

[Georgios48]

How often shall I have to replace bioballs?
I've heard that after some time they stuck with dead bacteria.

[MSD]

You don't have to change them, just rinse them out with tank water to slough off any debris. They last forever, or until the sun explodes. :)

[kirkp]

As MSD said, they will last for almost forever. The actual thickness of the biofilm where it's most effective is very thin. As time goes on, the biofilm will increase in thickness until the inner layer will go anaerobic which will cause the layer to slough off. You can let this happen or more preferably take them out and rinse them off.

Kirk

[salth20]

Short answer, never. Over time, you will find brown debris in the bottom of your sump. That is the bacterial slime washing off of the media and collecting. Smooth bio balls (pall rings, balls with rods, tri-packs, blocks with rods, i.e. bio blocks) are self cleaning. I only know of one media that holds onto bio film really well. They aren't made any more, but you may find them on eBay. Thiel Aqua Tech made some really trick textured balls called Super Techs at one point. The drip "rods" were actually small hollow tubes, that slowed water flow so that the dripping water spent a lot of time in the bio chamber. Good stuff from a day gone by. I see no reason to disturb a filter.. a simple vacuum of the mulm or debris in the sump about every three months should be sufficient. BTW, I like putting a submerged media under the bio tower in freshwater systems. Ceramic rings, sintered glass, something. Makes life really easy when another tank needs to be set up quickly, and adds a little insurance, IMO.