ACTIVATED Carbon

So does anyone on here know for sure if activated carbon in your filter is bad for a planted tank does it remove things that plants need to florish?

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Permalink Reply by seth roach on October 31, 2012 at 7:45pm

haha you posted in the do not post in this section section. but yeah my planted tanks do better without it i mean if you just using root tabs no other ferts it prolly wont make that big of a difference but if you dose liquid ferts and use activated carbon your basically wasting most of your money....and using it would probably effect plants that get most of their nutrients from the water column like mosses or water sprite opposed more root feed plants like crypts and swords....

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Permalink Reply by LED on October 31, 2012 at 8:06pm

Activated carbon have pores that can catch large molecules. Tannins, large organic particles, and large synthetic particals can be caught. That being said I believe it also catches humic acid, and chelated nutrients, including substances like seachem flourish excel, and API co2. Your plants will become deficient in these micro chelated nutrients, humic acids which break down to give co2 and ammonium nutrients. Also takes out tannins which make the water tea colored. If you're doing a black water tank you don't want activated carbon.

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Permalink Reply by ŦůRbö ۰ Ҏяѻ ۰ on November 5, 2012 at 7:59pm

Carbon will remove potassium and other trace and minor elements if they are in a specific form, which is pH dependent. For most elements, the pH must either be below 4 or above 10 for them to be in a chemical form that can be absorbed by carbon. Under most conditions, carbon has a functional life of one to two weeks, perhaps even shorter. The average functional life of carbon is difficult to determine as many variables apply, such as the amount of dissolve organics in the water, the effectiveness of mechanical filtration, and the amount of carbon in use.

A safe assumption is that carbon’s functional life in most tanks will not exceed 2 weeks. With this assumption, a best practice is to replace half of your carbon weekly. This will result in fresh carbon within the tank for each week with no carbon remaining in the tank for longer than two weeks.

All carbons will release some amount of phosphate but some inexpensive carbons are acid washed in phosphoric acid and these carbons will leach a substantial amount of phosphate into the water (which promotes algae growth). However, all carbons from reputable manufacturers are currently acid washed with hydrochloric or sulfuric acids. These will leach very little, if any phosphate. Provided you are not a reef aquarist (and since this Post is about carbon use in a freshwater tank that is unlikely) the amount of phosphate leached is irrelevant.

Regardless, phosphate concerns can be eliminated by soaking activated carbon in a saltwater solution for a few days prior to adding it to your aquarium (but will harm live plants). Carbon can mask problems. As an example, a dead rotting fish in a tank will normally cause the odor of the water to change. In the absence of carbon this odor may be detected by the aquarist who may then search out the cause, find the dead fish, and remove it from the tank. If carbon is in use, the odor of the water may not change, and the dead fish may be left to decay potentially resulting in problems far more significant than a smelly tank. I prefer not to use it in a planted tank; it will remove most of liquid fertilizers, and ALL medications. The main reason people use it is to remove smell and the chemicals they add to city tap water. But with weekly or twice weekly water changes there will be no smell, and the use of a quality water conditioner will remove chlorine and other chemicals in the tap water. Carbon dust can cause major problems as well, like HLLE, HITH (Hole in the Head) and others. Refer to http://www.coralmagazine-us.com/content/activated-carbon-hlle-smoki...

Hope this helps, I believe it has more cons then pros in a planted or reef tank.

I also found this interesting:

http://www.thekrib.com/Plants/Fertilizer/keslar-carbon.html

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Permalink Reply by GSP on November 6, 2012 at 5:58pm

For planted tanks, it is a normal practice to use carbon during the first 1-2 months of a tank setup. Then move over to 100% Bio media. The biomedia is important to generate Nitrates for plant use, by converting the significantly more toxic and algae-encouraging Ammonia.

As everyone above has started, yes- it's counter intuitive to use carbon in a planted tank that is close to balance.

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Permalink Reply by TONY K on November 6, 2012 at 7:06pm

thanks for the info everyone, i love how the activated carbon keeps my water crystal clear, but after 3 weeks of use i noticed some leaves starting to yellow on my anubias, i think the carbon was absorbing the liquid ferts that i was dosing! so i took it out!