Activated Carbon Thoughts

http://www.3reef.com/forums/blogs/nasageek/activated-carbon-notes-417.html

I'd be interested in your feedback on this write up.

Mark

 

reason for slow flow? seems unnecessary for what carbon does. sure the water coming out of the chamber will be cleaner but in that extra time the water in the tank will be dirtier...
The reason phosban is low flow is it will breakdown I think.


Did you do any research on the potential downside of absorption? such as losing trace elements or food for inverts as it does filter organics too?


other then that good article covers the basic facts

 

A couple of comments.
First carbon works by adsorption not absorption.
The biggest reason for slow flow through granular carbon is it is a soft product which decays and breaks down easily, high flows result in erosion into dust of fines. Another is in order for carbon to adsorb the contaminants it must have contact time. Carbon is made up of billions of tiny pores or pockets which adsorb the contaminants, you must give the liquid time to enter the pores with a low enough velocity it does not pulverize the carbon.

 

This is taken from one of the articles I link in the summary. I'll summarize it better.

 

With respect to this question:

Here is what I found... I'll beef up that area as well.

 

With respect to this question... here is what I found... I feel breakdown is a valid concern also... I'll beef up that area as well.

 

I wonder if its because even the center of the carbon gets flow or if its because crushing it up destroys pores?

 

You may want to use a couple other research sources too. Two oth the largest carbon manufacturers in the drinking wtare industry are Norit-Americas and Siemens Water Technologies. They both have tons of data on their websites and you might be surprosed to find out they probably supply all the aquatics vendors at the wholesale level. I know for a fact all the GFO products in the hobby come from two or three manufacturers like Bayer Chemical and Severn Trent that we use for all our drinking water treatment plants.

 

Thanks.... I like researching this stuff so that I'll truly understand. I like seeing all the opinions out there. I found one article that COMPLETE contradicted another. GAC is a relatively "easy" thing... or so I thought.

What got me started on this was reading the forums I saw someone state that they don't use GAC.... I wondered why???

I'll keep sniffing around some just out curiousity.

 

Nice blog Mark. Only suggestion I have is in your conclusions you say; "Granular Activated Carbon (GAC) removes metals and inorganic/organic impurities from the water. By doing so, it improves water quality and clarity. There is also some speculation between maintaining low organics and impurities relating to lower incidents of disease.

The potential downsides of GAC are that is could enable phosphates leaching into the water and detritus trapped in the media filter could add more nitrates to the water column. In addition, GAC could remove small amounts of trace elements from the water column."

This is a repeat of what you already mentioned. I would skip that part (remove) and make recommendations there, i.e. when you think carbon could/should be used in reference to the stock load of the tank, things like that. The medication aspect is viable. Over all a good blog.