When Do You Replace Your Filters?

[darryl864]

I suppose I just wanted to get rid of the carbon as it wasn't doing anything. Would there be a large population of bacteria in there though? When I do take it out it would mean the tank would go through a mini cycle?

I think I'll just pop in some more foam as I tend to rinse the whole thing out when cleaning anyway.

 

[rabbut]

A tank is always theoreticaly undergoing a mini-cycle, but on a scale so small that we can't see it with out test kits. Doing anything to the media could potentialy make the situation worse, though not necissarily to a point where we can see any effect on our tests. It's only when we can read ammonia or nitrite on our test kits that we would tend to worry about it You can usualy get away with changing upto 1/3 of you media out in one go, or cleaning half of the tanks media without seeing any detrimental effects
In short, so long as no more than 1/3 of your media is carbon, remoing it all in one go would not be a worry. It will be a bacterial nesting place, but it won't hold the majority of the bacteria, hence it should be safe to get it all scrapped If you are looking for low maintanace, add the ceramic rings, if you are prefuring a bacterial nesting place, add fine sponge.
Most media choised with exturnals comes down to what you want out of your filters

All the best
Rabbut