carbon Pet of the Month
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New Member
Jul 1, 2004
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Hi all
I have had my tank now for a good 6 to 8 weeks, all was well until for some reason the ammoniaia levels went sky high, nothing i did brought them down, not water changes, not adding good bacteria, nothing, then i find out that the carbon in my filter needs to be changed every month, no one ever told me that befor. Carbon will absorb the ammonia till it cant absorb any more then it will start to release it back into the tank, now that i have a good supply of new better carbon i have my tank cycling again, basicly had to start again.
So to all you newbies out there, if you have carbon in your filter, dont forget to change it.

I haven't used carbon in my filter for ages

when i did, i never changed it

i never had any ammonia problems....?
i have a similar thing with my tank now.
I've never used carbon filters, and i am fully fishless cycled (i have very high nitrate) but my ammonia is at about 2.
What could cause this?
the only thing i know is that i have a 4foot tank which holds about 300litres
i have had 13 fish, being 6 mollies, 2 angles, 3 clown loach and 2 gaurami
i lost 1 gaurami and 1 loach jumped out of the tank.
being that i have such a large tank i have an out of tank filter, it uses 2 lots of sponge, carbon and some other stuff that apparently hold the nitrates in it,

all was well with my tank for over 6 weeks then i lost the gaurami and wondered why as the water was normal, a few days later the amonia spiked, but never got higher than about 1.2

after about 2 or 3 water changes, and nothing but the amonia going up, i went to my lfs and they said to change the carbon, i did that and now the amonina is 0 and the nitrites is up at about 0.8, so because i wasnt told about the carbon befor i have to now go through the cycling process again

i have been worried about the fish i have left but so far they all seem to be fine and show no side affects of the bad water

i now hope the water will correct itself and finish cycling as i would like to buy a couple of sucking cat fish

keep you fingers crossed for me please
IMO carbon isnt necassary (spelling right?) to have in your tank all the time.

However you could use it for the following:

1. To remove medication from the water (after you have finished treating fish)
2. If if have bog/drift wood in your tank which is new and releases tannins into the water and turns the water browny.

All i can think of. :unsure:

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