Activated Carbon: Yea or nay? Why?

[stanlalee]

Originally Posted by cloak

Assuming GAC is removing the smell, the yellowing, the organics, etc, taking this "dirty" water out of the tank and then replacing it with freshly made saltwater is pretty much the same thing I guess. That bucket of freshly made saltwater is as pure as it gets though. I know what I'm getting through water changes. No worries about what it might leach, what "good" stuff it might remove along with the bad, no HLLE speculation, nothing. To be honest with you, I really don't think anybody knows for certain how long carbon lasts. Just as an example, let's say you replace your carbon every 2 weeks. Well, after five days in the smelly yellow tank water it has exhausted itself, it's done. If you weren't seeing anything out of the ordinary when it was time to change it out 14 days later, you have pretty much been going without carbon for the last 9 days. This type of thing happens all the time. Lets face it, GAC could fall off the face of the earth and we still get by. Water changes, no so much.

Happy reefing.

I'm sorta with you in that in 15yrs of keeping saltwater I have yet to notice any visable or hobby grade testable subjective/objective difference with or without it. water doesn't look any clearer. water doesn't test any better. no livestock looks any better or worse. that said I am running it currently HOPING it may be having some effects on more than meets the eyes. for example perhaps there's a line of water clarity not visable to me but noticeable to coral photosynthesis. this would perhaps likely be no more than the equivalent of a couple months of bulb wear at best (something else I wouldn't notice). Perhaps it pulls a few more organics out simular to a moderate skimmer upgrade. people talk all the time about upgraded skimmers pulling more crud but lets be real even though its working better, 98% of the time unless they had undersized garbage before there is no visable/measurable benefit in the increased productivity. even though I too feels its completely unneccessary (some might say the same about skimming ect) I am confident its doing SOMETHING wether its worth my effort to use it or not. If it were expensive or hard to apply I wouldn't bother but as cheap as it is I'll never go broke or miss any meals due to a cup or two of carbon every few weeks.

[Dalmerjd]

I use carbon 24/7. I use the bottom 4 inches from a Walmart basket filled with carbon in bags. I use excess pump capacity and flow water over it. The basket is suspended about an inch above the water surface in my 180g sump. I change the carbon once a month and rinse it out every 5-7 days.

[lougotzz]

I have it in a reactor. Its costs like 50 bucks with the reactor and pump so I just put it on in the begining.

[DarkXerox]

Given the recent studies I've read regarding skimmer performance and how even the best remove only a fraction (20-30%) of total DOC (dissolved organic carbon) link, I've started using GAC (granular activated carbon) again after not using it for 2 years. Skimmers only remove components that have distinct hydrophilic regions with hydrophobic areas as well (think of lipids and their polar heads with nonpolar tails). Kind of makes me feel stupid for letting hobby knowledge trump my biochemistry knowledge for the past couple years!

The use of Disodium fluorescein in this study link is pretty interesting and you can see how the rates vary based on initial DOC concentration, tank volume, and the # of grams of GAC used. While I do question some of the fluorescein drop, due to peroxyl radicals decaying the fluroescein over time (part of my graduate work), the levels of ferric and ferrous iron in our tanks should never be high enough to fuel the Fenton reaction leading to a high level of peroxyl radical formation. Or at least we should hope not!

The other things interesting from that study are how little GAC is needed to achieve t90 (90% removal of DOC). Assuming a well-skimmed tank has around 1ppm DOC according to their work, 1 gram per gallon of water will last you approximately 30 days before saturation.

They did show how saturated GAC does release compounds very quickly back into solution (assuming equilibrium is reached, or [DOC]carbon is higher than [DOC]water). So swapping it out sooner would not hurt given how cheap it is.

In addition, their work showed Hydrocarbon2 from Two Little Fishes was outperformed by Black Diamond from Marineland (as far as the rate of removal "k" was concerned and final [DOC]).

I found it all to be extremely interesting since it is very rare that I actually see studies in reefkeeping that go through the trouble to properly set up and report data.

[Randy Holmes-Farley]

Given the recent studies I've read regarding skimmer performance and how even the best remove only a fraction (20-30%) of total DOC (dissolved organic carbon) link, I've started using GAC (granular activated carbon) again

Although there's no equivalent study as to the percentage typically removed by GAC. I do not believe the model using an easily bound dye is at all comparable to a real experiment measuring DOC.

Skimmers only remove components that have distinct hydrophilic regions with hydrophobic areas as well (think of lipids and their polar heads with n

The same could be said of GAC: it only remove organics with some hydrophobic portions.

[no_Wedge]

it does help on smell and maybe some on clarity, but mainly the organic compounds which contribute to smell.

[SS21CA]

When I had a full tank of fish, w/o activated carbon the water would yellow and have slight odor. It makes a world of difference. I did have a high amount of bio load at that time, but even now that I have less fish, the water is more clear. From side to side if you look through the tank it is crystal clear. a must IMO.

Throw it in the sump, replace it every few months.

[thebanker]

It seems to me that the more diligent you are with water changes, the less you need activated carbon. (not to mention every other method of filtration out there)

If you're like me, and do water changes sporadically at best, it's probably better to have it than not. It's like - if you shower 3 times a day, you may not need deodorant.

[thebanker]

Originally Posted by Randy Holmes-Farley

I do not believe the model using an easily bound dye is at all comparable to a real experiment measuring DOC.

+1 on that. With the myriad of DOC's in our tanks, a single organic dye is not the best comparison to use. Hey at least we have some evidence to boost the pro-carbon argument.

[anj1204]

IMO if you have a mixed reef you should run carbon. The carbon helps filter out the toxins that can be released by various corals. I run it in a bags in my sump.

[onetrickpony]

Advanced aquarist has some great articles on the use of GAC
Boomer has some great information in his posts on GAC
Boomer and Randy are great resources
http://www.advancedaquarist.com/sear...chableText=gac

[spamreefnew]

24/7 because i think it helps with chemical warfare . toadstools vs sps

[tjmarty]

I run mine in HOB filter in a media bag for right now,in a 55gal doing a 75 gal build , and already have a reactor for the carbon. You never know what and when a toxin can enter your system, it can come in on your hands ,or something could get droped into the tank or the sump, you just never know!

[OoooDRAGONoooo]

Hi,i have been using it for 6 months,I have just stopped,because I'm concerned about my high nitrate readings.,also I just discovered on the packet of carbon I use ,it says freshwater use only.so is it leaching phosphate ,I don't know.im going to dose vodka to get it down .wish me luck!

[KRBNSOL]

bag in sump - but would like to move to a reactor

[Zacktosterone]

Originally Posted by thebanker

I'm on 2 weeks of carbon after 4 months off. My skimmer is only pulling out about 1/3 the amount of skimmate it was before. In my opinion, that's hard evidence that the carbon is reducing organic material in the water.

Also I started running a sponge filter to remove particulate matter in the water, which may skew the outcome a bit.

So isn't that not hard evidence then?

[thebanker]

With all the processes going on in these tanks, it's hard to say for sure if event A was linked to Event B.

FWIW, I still run carbon off and on.

[tmz]

I've run my system with rox carbon from BRs for many years. I like the rox because it has little dust and reequires jsut a brief rinse and since it's denser than most it doesn't grind up easily and doesn't put fines in the water. I use about 20 ounces for 650 gallons a water volume which is about a quarter of the generally recommended amount and change it every 2 to 3 weeks

[kinnadian]

Funny how this 5 year old thread has started up and people are just replying as usual.

Is cheap carbon bad? I've read that the processes used to capture cheap carbon are really nasty, like repurposed coal waste etc.

[tmz]

It can be. A major brand put out as reef carbon nice large convenient pellets that actually had pore size rated for air and wasn't an aqueous carbon. That won' hurt anything but it wont work well in reef tanks either. The bad part is that batches of this then popular brand were put out with heavy metals picked up in the processing. The manufacturer had changed suppliers without telling anyone of course. Many tanks tragically crashed.

[Isaacs55]

So it seems a lot of people agree on using it. My question is, if it's better to use it in a reactor or a filter bag in a high flow area of the sump?

[tmz]

Anywhere you can get a good flow of water to pass through it. I use a reactor for some and an old cansister filter for some. In a pinch a loosely packed fine mesh bag in a high flow area will do.

[Buzz1329]

Thanks, OoooDRAGONoooo, for resurrecting this thread.

Interesting reading.

FWIW, I have used GAC in every tank I have run. Currently using BRS ROX in separate reactors in both my tanks.

Mike

[trueperc]

I have been using carbon in a reactor for years. There was even just a recent bulkreef supplies video showing how the yellowing water can reduce par. I always loved the look of the water with carbon. I have always understood though that is gets used up quickly so I have always been under the impression use smaller amounts and change regularly. What about mixing different carbons of different sizes?

[laga77]

There really isn`t a reason not to use it. I use it in a reactor, pellets I get from Ebay. After rinsing, add a little filter floss to the top of the rector and control the flow so there is no tumbling. About 2 cups worth on my 120G and half that on my 50G, changed monthly.