Dasha

I was wondering what you keep in you canister filter and why?

Do you use activated carbon and/or zeolite? What else?

Thanks.

Isabella

I have a 75 gallon planted tank so I can't have activated carbon / charcoal / zeolite in my canister filter. These chemical media will remove all nutrients from the water that are necessary for plant growth. What I have in my filter are a lot of sponges and a lot of biological media. For bio-media, I use Eheim's Ehfi Substrat ( http://www.fishlore.com/Forum/index.php?topic=6937.0 - scroll down to the pictures with the filter and filter media to see what it all looks like ). Various bio-cubes can be used as well. Also, on top of the bio-media I use micro filtration pads ( http://www.bigalsonline.com/BigAlsUS...crofiltration2 ) to remove the finest particles in water.

In my 30 gallon tank, I don't have live plants, but I don't use activated carbon / charcoal / zeolite in this filter either. If you have good water changing habits and do not overstock your tank(s), you don't need chemical media in your filter at all. Instead, I use 2 sponges in my filter (the 2nd sponge is sitting where the chemical medium is supposed to be). And of course, the bio-cubes for biological filtration. This filter is a HOB (Aqua Clear).

jsalemi

The plants column in the Sept. issue of Aquarium Fish International addresses this very point, and disputes the 'common wisdom'. His reasoning is that the size of the molecule of the vast majority of nutrients that plants use is too big to be absorbed by the pores in todays activated carbon. He makes a fairly reasoned case for his point of view.

Isabella

Well, I am not very familiar with this detailed aquarium chemistry, and they may be right for all I know. But even if they are right, I still don't need activated carbon / charcoal to keep my water clean. It's not "absolutely" necessary in a tank, unless your tank is overstocked and your water changing habits are bad. Anyway, I'd still be afraid to use activated carbon / charcoal in a planted tank. Most people I've talked to on PlantGeek.net don't use chemical media in their filters (in their planted tanks). To tell you the truth, I don't see the difference in water clarity whether using activated carbon / charcoal or not, so I might as well not use it. But, of course, if anybody wants to use it, it's up to him/her