question on biological media..

smit3183

I have the fluval c4 filter and it says to replace half of the c nodes every 6 months. Is this necassary? And if I don't will it lose it's effectiveness as far as reducing toxic ammonia/nitrite and giving off oxygen, Ive seen on this board many times not to change out any mechanical/biological media unless it's completely falling apart.

zof

Unless they fall apart I would just give them a good scrub down, sure some pours might get blocked but nothing major unless you notice it can no longer keep that much biological filtration going. Remember filter makers also make the replacement filters so its in their best interest to tell you to replace media you don't really need to.

Byron

Replacement as zof said is normally not necessary. But regular cleaning (rinsing) is, or the filter may very well not perform biological filtration.

The media attracts nitrifying bacteria that form a biofilm and stick to it. Other bacteria can colonize too, and will smother the nitrifying if they pile up, so to speak. Regular rinsing prevents this, so the nitrifying bacteria will remain effective. You can read more here:
Bacteria in the Freshwater Aquarium

The frequency of rinsing depends upon the tank's biology, but weekly during the partial water change--and rinse it in a pail of tank water--is prudent with an HOB filter.

Byron.