Does activated carbon release toxins when old?

[pejerrey]

As the title says.

Sounds to me a bit illogical but I want the extra geeks to chime in here.

True or myth?

I'm close to a canister service date and I was planning to use some carbon, it's a 29 gallon planet shrimptank. How much should I put in there?

Thanks!

 

[Yo-han]

Hmm... Don't know for sure but I don't think so. Not under normal conditions at least.

 

[ShadowMac]

It doesn't. It would if exposed to EXTREME heat, but under our uses and most any non industrial uses would not leech "toxins" into the water.

Biollante could most likely source this info...i'm using him as my source.

 

[Tom Barr]

A lot of the chemicals that are taken in by carbon ends up attacked later by bacterial colonization.
These are broken down into smaller parts, eg, CO2, O2, H2O2, Cl-, PO4 etc........

Old carbon ends up becoming biomedia.
So after about 1-2 months max, it's just good for biomedia.

Some folks reheat the carbon and reuse it.
We use to do this in an over and cranked the temp as high(500-600F) as it would go for 2 hours or so.
This oxidizes much of what the carbon took in......

I think you'd be wiser to use an in line filter and a small pump. Then run this once a week etc for a few hours.
I use carbon for prefiltering in my tap water refill at my client's(all of them actually).
But I rarely would use it in the tank.

Purigen would be more suitable over time I would think/suggest.
But, I think a water change is far cheaper and easier than adding/using carbon.