Carbon Replacement... Carbon- Or Filter-Driven Decision?

[simonero]

Hey guys,
 
I have a quick question about carbon that I'm hoping someone can answer.
 
Does carbon go "bad"?  When we change out the carbon in our filter, is this because after too much time it loses its filtration properties, or because we're keeping the filter/filter materials around the carbon clean?
 
Sorry if this is a dumb question; it just occurred to me that I am unsure and I don't want to buy new carbon if I can recycle it with a little maintenance.

 

[StevenF]

Activated Carbon in your filter is a spunge that absorbs organic materials and nitrogen in the water.  When it can no longer absorb any more material it must be replaced.   The same is true for phosphate absorbers.  
 
Other materials in filters are intended to provide a place for beneficial  bacteria to live and these do not need to be replaced.

 

[RainboWBacoN420]

I haven't been running carbon in my filter for my 55 gallon for months now. I don't find it entirely necessary, but I've been thinking about placing a filter sock with carbon in there just to make my water clearer. I haven't had problems with nitrates or phosphates as of yet, and I barely do water changes, just top off the tank whenever needed.
But yes, carbon is said to expire after two weeks.

 

[StevenF]

 
 
I haven't had problems with nitrates or phosphates as of yet, and I barely do water changes, just top off the tank whenever needed.

Phpsphate and potassium levels can increase quite quickly  in as little as a week simply because we add food to the tank daily.  Also as water evaporates minerals in it concentrate in the tank, increasing your water hardness.  You haven't had problems yet, but you are doing everything necessary necessary to create those problems.

 

[RainboWBacoN420]

 

 
 
I haven't had problems with nitrates or phosphates as of yet, and I barely do water changes, just top off the tank whenever needed.

Phpsphate and potassium levels can increase quite quickly  in as little as a week simply because we add food to the tank daily.  Also as water evaporates minerals in it concentrate in the tank, increasing your water hardness.  

I made that post right before I tested my water and posted that other thread about the nitrates. So I was lying!
 
That's actually very odd, because my hardness seems to have gone down by 1-2 ppm, maybe it's because I shook the solution first before using it and it yielded a different result. 
 
 

 

 
 
I haven't had problems with nitrates or phosphates as of yet, and I barely do water changes, just top off the tank whenever needed.

  You haven't had problems yet, but you are doing everything necessary necessary to create those problems.
 

Harshly put...