Two Little Fishies Hydrocarbon 2 Granulated Activated Carbon

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Two Little Fishies

TwoLittleFishies HydroCarbon 2 G.A.C. is a granulated activated carbon designed specifically for the purification of water. It is manufactured by steam activation and acid washing of a special Lignite material under carefully controlled conditions to produce an activated carbon most suitable for aquariums. Since it is extremely porous and positively does not leach phosphates that can stimulate the growth of algae. It has a very low ash content and therefore hardly affects pH. HydroCarbon 2 G.A.C. has a wide range of pore sizes and large pore volume that provide a rapid adsorption rate plus a high capacity for dissolved organic compounds. It has the highest capacity for removing water-yellowing tannic and humic compounds of any commercial water activated carbon, and adsorbs both large and small molecular pollutants, including defensive substances released into the water by soft and stony corals. The macroporous structure of HydroCarbon 2 G.A.C. also affords a high ability to resist clogging that can interfere with the adsorption of dissolved organic substances. The granules are the optimum uniform size for use in high capacity filters, allowing even-flow of water at high velocity with minimal back pressure. HydroCarbon 2 G.A.C. has a long useful life. After months of use it also becomes a very active biological filtration community full of beneficial bacteria and microorganisms. It can thus be used as a biological nitrification, denitrification media, or to seed new aquariums with active bacteria cultures.

Use approximately 125 ml (1/2 cup) of HydroCarbon 2 G.A.C. per 50 gallons. Entire contents will effectively treat 200 gallons. Pour the required quantity into a polyester or nylon filter bag. Carry the dry bag of HydroCarbon 2 G.A.C. outdoors and also bring a container partially filled with tap water that will be used to rinse it. When outside, immerse the closed bag into the container of water. The porous carbon sizzles a sit becomes hydrated, and carbon dust is released into the air and rinsing water. Do not breathe the dust! Shake the bag underwater and lift and immerse it again repeatedly in order to wash out most of the fine dust. The black water produced is safe to pour down a drain, or into the soil outdoors.

Locating the HydroCarbon:
For the most rapid removal of water staining organic and other pollutants, place the bag of pre-rinsed HydroCarbon 2 G.A.C. in a filter chamber where water flow is directed through it. Use filter floss before the bag to trap fine particulate matter that could clog the bag. May be used without a filter bag in external powerfilters by installing filter floss above and beneath the carbon to retain it. Important: When it is being used in a high-flow filter chamber, be sure to close the bag so that the carbon is kept tightly packed. This will prevent the granules from tumbling, which could liberate carbon dust into the water. HydroCarbon 2 G.A.C. can also be used passively, without filter floss, by locating it in a filter chamber in such a way that water flows over and through the bag but is not forced through it exclusively. Continuous use in this passive manner still effectively prevents the accumulation of yellowing substances, keeping the water sparkling crystal clear. Replace with new HydroCarbon 2 G.A.C. as needed to maintain the colorless water. Normally effective for several months.

Keep this container tightly closed to prevent air pollution from being adsorbed. Do not use HydroCarbon 2 G.A.C. when medicating the aquarium. Can be used to remove medications from the water when treatment is complete, but should be discarded afterwards.

HydroCarbon 2 G.A.C. effectively removes ozone when located at the water stream exiting an ozone contact chamber such as a protein skimmer or oxygen reactor. When used for this purpose it should be changed once per month.

Rapid removal of yellowing substances dramatically affects the penetration of light in water, particularly UV light. This can adversely affect corals that have become acclimated to the light spectrum altered by the yellow water. They are unable to tolerate sudden exposure to UV wavelengths. If no activated carbon has been used for long periods without water change, be sure to shade the corals when the carbon is used again, and gradually acclimate them to the light over the course of a few weeks. Keep out of reach of children. For aquarium use only.

Reef Chemistry Calculator
Use our chemistry calculator to find out how much you need to add to your aquarium.

Manufacturer Info

Two Little Fishies
Two Little Fishies, Inc. was founded in 1991 to promote the reef aquarium hobby with its introductory video and books about reef aquariums. The company now publishes and distributes the most popular reef aquarium reference books and identification guides in English, German French and Italian, under the d.b.a. Ricordea Publishing.

19 Reviews

Robert Rueckert from Gainesville, GA UNITED STATES


Experience Level: Expert

Clean & Effective

I have used every activated carbon over the past 40 years and this is the best. Basically clean and de-activated which makes it easy to adjust to saltwater chemistry without shock. Cost a bit more but worth it!

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kenneth hickey from sparks, NV UNITED STATES


Experience Level: Intermediate

Best Ever

Product is the only carbon that does not place back pressure on my pump and does not leach Phosphates.

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C. Covington from Reno, NV UNITED STATES


Experience Level: Intermediate

Very Good Product

Does what its supposed to. Has that satisfying 'snap crackle pop' when you rinse it off! Keeps my 100G FOWLR water crystal clear. Recommended.

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Experience Level: Intermediate


It's an excellent product, work very well

1 out of 1 found this review helpful

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Experience Level: Intermediate

Works Well!

I would like to start by saying I do not have any issues with dust as others have mentioned, and I have been using this product for more than a year already. This is why. I use the Two Little Fishes Phosban reactor. I fill the reactor to around 80%. Now here's the key. Instead of only adding the sponge at the top of the reactor, I add the sponge and then add a 1 inch layer of filter floss over the sponge. When water passes through the reactor, some dust is stopped by the sponge at the top, and the rest is stopped by the filter floss, so only clean water ends up coming out of the hose. So I do not wash the carbon at all, I see no residue in my sump or my display tank. I change the carbon monthly and it's painless because I do not need to wash the carbon. Try this and you will see. Another important note. Water should pass through the reactor very slow. If you crank up the power then of course dust will get into the tank. Anyway, no issues with phosphates and the water is crystal clear. No issues with any of the corals or fish either from using the carbon 24x7.

6 out of 6 found this review helpful

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Experience Level: Expert


This keeps my water crystal clear. The only downside is that you have to wash it allot in order to get it clean. Otherwise all of the dust will deposit in your tank.

1 out of 1 found this review helpful

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Experience Level: Expert

its good but

this seems to be working well but it seems to be taking way to much effort to get all the black dust out of this carbon. lets put it this way, just imagine filling a 5 gallong bucket 5 times atleast with pure black water results and then after 30 mins of cleaning this and putting it in my reactor my filter sock was black and fish were stressed. the biggest waste was that i was using ro/di water i believe with any type of carbon you can only wash it so much before it starts to reduce the quality of the carbon i have 0 phosphate though so im guessing it doesn't release phosphate

2 out of 2 found this review helpful

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Experience Level: Intermediate


This hydrocarbon was really great, my 120 gallon reef aquarium water crystal clear after 4 days use. Coral open longer and enhanced colour. I also use this hydrocarbon to my cleaner shrimp breeding tank. Amazing result.

1 out of 1 found this review helpful

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Experience Level: Intermediate

Good Carbon at a Great Price

I have always been a fan of products from TLF, and their carbon doesn't disappoint. I change out the carbon in each of my tanks approximately once a month, and throughout each month it certainly helps keep the water clean and clear. So far I have not noticed any leaching or release of phosphates back into the water, a good thing. My only let down is that this is another brand of carbon which requires a decent amount of washing first to remove most of the carbon dust. Regardless, TLF Hydrocarbon is great for its price.

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pickle from


Experience Level: Intermediate

great stuff

i've used a number of different brands of GAC and this is the best by far-- makes the fish look like they are floating in air.

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