Activated carbon to dechlorinate water changes??

[midman]

I have just recently bought some activated carbon to dechlorinate my tap water for water changes. I have a section of hose pipe filled with it and I trickle water through it slowly. Is this a good way to do it other than standing the water or by use of dechlorination chemicals?? I also run in the same line an ion exchange resin which removes the nitrate - again hose pipe filled with the resin. I am guessing the water is being dechlorinated but wonder if any other chemicals that should be there are maybe being removed. Or does that only happen in the instances of RO water?? Any help would be appreciated.

[Gary Herring]

I might be wrong but im pretty sure carbon wont take out chlorine or especially not chlorimine. Not the way your using it anyway. Its different in an RO unit because the water gets forced through a solid carbon block. I'm assuming the carbon you are using is granular or powder, in which case the majority of the water would follow the path of the least resistance through the tube and by-pass it. Only a small percentage of contaminants are removed each time water is passed through granular carbon, so you would need to repeat the process several times, and even then it might not remove the all the chlorine. I'd use a de-chlorinater.

[NancyD]

Many fish like loaches a quite sensitive to even small amounts of chlorine & chloramine. Sounds like you have a home-made water changing system like a Python? I think people add enough de-chlorinator to the tank to treat the entire water volume,not just the replacement quantity, BEFORE adding new water. It's fast & safe that way, & shouldn't be expensive compared to carbon.
Nancy

[Mark in Vancouver]

The carbon system you describe will not remove enough of the chlorine (or chloramine, depending on your water supply). Get some aquarium-ready dechlorinator from ANY fish shop, and add it to your water before the water goes into the tank.

Activated carbon is used to catch dissolved organic matter in the water, but it will also remove some other chemical impurities, including chlorine and tank medication. But Gary is correct - water has to cycle continuously through the carbon to have the desired effect. The process is gradual.

[midman]

Maybe the issue here is more to do with the flow rate. I agree with the point made about the water taking the path of least resistance. I am passing my tap water through a 70cm length of 1 inch diameter hose pipe at a rate of approx 100ml per minute. It also takes quite a bit of pressure to do that. I am presuming that provided the bed of carbon versus the flow rate is sufficient then it should, when working efficiently remove all of the chlorine. I have been using chemical dechlorinators but I wanted to find a more environment friendly way of doing this and that was my only motive. I am trying to find a good chlorine test kit to check when the carbon is saturated but don't seem to be able to find one. Does anyone know of a supplier, or even worry about it at all.

[Gary Herring]

Yeah i suppose it might work. I probably would'nt risk it though to be honest. I dont think carbon is as effective at removing chlorine as it is stuff like DOC's, odours and dis-colouration.

[Mark in Vancouver]

Carbon is "activated" through chemical/mechanical processing. Environment-friendly? I don't know that it is. There may be other aspects of the aquarium hobby that will offer better potential in this pursuit.

[Gary Herring]

If its environment friendly your after, why not collect rainwater to use in your tank/s? Thats what I do, and its especially good if you keep fish who prefer softer water. Make sure you partially re-mineralise it though, rainwater does'nt contain much (if any) Kh so you'd need to buffer it a bit. I use mineral salts from the LFS but you could just add some tapwater as long as its fairly hard. Only potential problem with this is if there is a severe source of air pollution close by, such as a factory chimney or something. If this is the case filter it through some, yep you guessed it, carbon!