About carbon

[Krish]

I was thinking about adding in a small section in my sump (out of acrylic)where I could run some carbon rather than in my cannister filter. Where I was thinking about putting it, it would be where the first chamber spills over into the second chamber which means it won't be completely submerged. Can carbon be used like this or does it have to be completley submerged? I figured that all of the water passing through the sump will have to pass through the carbon (which will give the carbon a greater chance at coming in contact with the water) however, where I want to put it, it will be closer to the top of the sump, where the water spills over, rather than at the bottom of the sump completely underwater.

 

[CarlaW]

If it was me, I would prefer it to be totally submerged. I don't run much carbon, so maybe someone with a little more experience with it will chime in here.

 

[Krish]

Thanks Charlie. I've only ever known of running carbon submerged that's why I asked. I can do the same thing I want to do, just lower the tray so it can be submerged, but was curious if it had to be run tht way.

 

[wrightme43]

Its better to have it submerged so its not like a nice wet dry media. I occasionally just use a little for a few days but then my skimmer stops having all the fun so I get tired of it and take it out just to see my skimmer work.

 

[Curtswearing]

Yeah....you want it submerged. Carbon works by Van Der Walls forces and contaminates won't bind in the adsorption pores if there is air in there. In fact, you should pre-wet your carbon because of this.

In liquid applications, why is it important to deaerate (fully wet) the carbon?
A container of carbon is roughly 20% carbon, 40% interstitial space (the volume between the carbon granules), and 40% pore volume (the volume inside the carbon granules). If air remains in the pore volume, the fluid being treated cannot migrate to the adsorption sites. The air becomes a barrier to the carbon functioning properly.

How long does it take to fully wet the carbon?
Typically, Calgon Carbon recommends filling the system with the fluid you will be treating and allowing the system to sit idle for 24 hours. This time will allow the fluid to displace all of the air in the pores of the carbon. After the system has been idle for 24 hours, the next step is to use an upflow backwash to displace any air that has been trapped in the carbon bed. This backwash will also remove most of the carbon fines in the system.

http://www.calgoncarbon.com/resources/faqs.cfm

 

[mojoreef]

Good post Curt!!


Mike

 

[Krish]

Thanks for the replies everyone...

 

[Woodstock]

Interesting Curt! So soaking the carbon in ro/di water has dual functions now!!

 

[Krish]

So, is rinsing out carbon (which is being prep'd to go in the tank) in regular tap water bad? Will you then transfer nitrates and/or phosphates into your aquarium like this, or will it not affect anything until the carbon has exhausted itself and starts to leach if not changed? I know people wash out frozen foods in RO/DI water to prevent adding nitrates/phosphates, but do they do the same for carbon?

 

[Curtswearing]

Most QUALITY carbons are now acid washed to remove the ash content. That has dual advantages. You no longer get the pH swings that people used to experience with older carbons. They are also much lower in phosphate content than they used to be. However, they are not completely free of phosphate so soaking in RO/DI water does indeed serve dual purposes; it pre-wets (deaerates) the carbon, and it sucks out a lot of the remaining phosphates. In spite of recent advances, there are still differences so don't go cheap here. Unfortunately, there are still coconut husk and pelletized carbons on the market and those are Air Phase Carbons (APC) and not Liquid Phase Carbons (LPC). They are better than nothing but are quite expensive when you consider their effectiveness. (Even though coconut carbons are APC, they are quite effective at removing Chlorine so don't go change the carbon block of your RO/DI unit with more expensive GAC).

Rinsing the carbon with tapwater is not the end of the world. You'll rinse off the dust which is good but you won't remove as many phosphates. Soaking in RO/DI water is much better though. As far a leaching is concerned, carbon is no different than LR to a bacterium. Bacteria will create a biofilm on and in the carbon because there is housing space and food there. I want organic adsorption as opposed to another biofilter so I like to use a small amount, leave it there for a short time, and then remove. If you use a large amount and leave it there for a long time, you should just consider it a biofilter.

Protein skimmers also work by Van Der Walls forces but there is one huge difference...the contaminates that they get are exported from the system. With carbon, the contaminates are still in the system until you physically remove the carbon.

There is a lot more information here. http://www.reeffrontiers.com/forums/showthread.php?t=78

 

[CarlaW]

Curt, those are some excellent links!!!!!!
In one of them, he uses carbon for 12 hours a week, dries it out, and then reuses the same carbon. Do you know how often this can be done??
Thanx again.

 

[Curtswearing]

I truly don't have a clue as I've not tried this nor done any testing in this manner. If I were to even consider this, I would definately resoak in RO/DI water.

 

[Krish]

Thanks for the info Curt...Very interesting. I've always ran carbon continuously changing it out every 3 weeks. Never gave much thought to using it for a few hours a week. I guess when you first learn about aquarium keeping you tend to think that it is a must to have carbon in the system at all times, but I guess when you think of it potentially becoming a bio-filter if not managed properly, then it may not be the best idea. I may try that approach this time. I've already tossed a filter pad and a filter sleeve out of my system for the simple fact of it eventually acting as a biological filter and possibly causing more harm than good. I just have one pre-filter sponge which I clean or change every 2 days and what that doesn't pick up or my skimmer doesn't then I guess just runs back through the system to have another chance at removal. Thanks again for the info and replies everyone.

 

[NaH2O]

Here are a couple of threads with some additional good information about carbon use: Carbon Filtration Question and What Brand of Carbon Do You Use?

 

[Krish]

Thanks Nikki...

 

[MarineTeng]

You no longer get the pH swings that people used to experience with older carbons.

AHH is that why xenia might be faltering, i started using carbon, that definitely has ash, my hands showed that, though my one test was at 8.2 pH could i still be getting a swign cause of it, should i stop using the carbon now that it's 2 weeks after using FWE and all flatworms appear to be gone, and i've done a 30% water change?