Carbon Filters

[GaryD]

Hi,

This thread arose from a side discussion on carbon filters that happened on another thread. It's a worthwhile subject in its own right.


Gary

[Toga]

Hi,

Inadvertently, in hindsight and to my advantage it appears, I may have addressed any potential styrene toxicity issue already in my system...

Here - is an Assessment of Styrene Emission Controls prepared for the USA EPA.
You will find activated carbon is the key ingredient used for absorption filtering controls of Styrene. (p.12-14)

When I was assembling and filling 2x200ltr bio filters with bio-balls for my system, I noticed I had a couple huge 25kg bags of high quality activated carbon pellets left over from a previous business. Knowing the brilliant filtering & chemical absorption qualities of activated carbon when used filtering water, I thought, why not? ... and put a bag into one of the barrel filters.

Like a micro sponge, activated carbon is extremely porous. It has a brilliant high surface area structure for bacterial growth, high physical particle / solids removal as well as its massively high chemical absorption / filtration properties.

Activated carbon's high points are also its weak points.
It can quickly become full of fine solids and blocks up, creating water channeling through filter media and potential reduction of O2 supply to bacteria. Thus it requires regular cleaning. When 4 cups of dirty carbon is washed in a 20ltr bucket of clean water, you will be blown away by the filth of sludge that is released.

Cleaning / recharging carbon of its chemical waste build up is a different matter.
In commercial circles, specialized high temperature steam machines and / or curing ovens are used.
For smaller home scale quantities you can boil it, then bake it @250c for an hour .... another way I have used in the past to recharge carbon used in fresh water, is to run it in marine water for a couple weeks, then replace onto a fresh water system. (and visa-versa - marine to fresh does not work as well)

In home scale use & cleaning methods you can never expect to fully recharge the carbon of its chemical filtration properties. Periodic replacement with fresh carbon is highly recommended, every 6-12 months or so.
Carbon retains is solids filtering capacity for many many years, when cleaned regularly.

I use to recommend approx 1kilo of carbon per 1000ltrs (1g/ltr) of water to be filtered.
Using special filters, Diatom Carbon turns clear clean water into crystal diamond clear.

Definitely Not Recommended At All, without weighing up your personal system & potential risks.....
I have even used with great results, years ago in a large koi pond filter, carbon chips & chunks left over after a bonfire party.

Some 'Permaculture' circles produce & recommend a 'bio-char' for its great natural benefits as a purifying & cleansing agent for air, soil & water.

Addition of activated carbon to a home aquaponics system can be as easy as placing a stocking / net of it on top of your grow bed where the water first enters. $5 / 250g from most aquarium shops, small investment for huge piece of mind.


Cheers
Toga

[mopa]

yep i used carbon aswell, to filter water put into new and washed 1 month old drinking water fibreglass tanks, cause i´m cautious.
I also use it in the form of chikutan charcoal tubes (bamboo charcoal) in my expensive crystal red shrimp tanks. I also use seachem purigen. Good stuff

[Toga]

Hi mopa,

I also use it in the form of chikutan charcoal tubes (bamboo charcoal) in my expensive crystal red shrimp tanks.

Excellent - I use to breed crs, even managed some gold & platinum mosura & hino's... stunning little creatures.
PS - Platinum SSS grade Mosura sell for $750 - $1000 ea here.

Cheers
Toga

[mopa]

wow !! between thisAttachment 4460Attachment 4461 and my other tanks i would probably be a aus millionaire. darn chose wrong country to live in lol

[Toga]

Wow mopa,

Stunning collection !
... they are an illegal import to AU, hence the price. Not many quality shrimp breeders here.... and as you would know, they can be very sensitive.

Yes yes, back on topic .... that Sir is a fine example of achievable water quality when using carbon in a filter.

From memory, the highest grades of bone carbon are capable of filtering a very large % of most toxins, contaminants & elements. You can filter out the minute traces of gold that are found in marine water using carbon, you just cant extract it from the carbon afterwards

... and yes, that does also mean that too much carbon could / would filter out some / heaps of the micro & macro elements that the plants require.

Cheers
Toga

[mopa]

yep, i use osmosis water for them, then reconstitute water to ideal levels with additives, turn off carbon filtration, and dose microelements and calcium. lol
they live better than i do! Sometimes I feel i am not a keeper of shrimp but a maintainer of best water quality !
Do agree i find them stunning still- 5 years later. regards

[GaryD]

Hi,

This is an important subject given that many people operate "closed loop" systems where the main way for any toxins to leave the system is through uptake by fish or plants and subsequent consumption by humans.

If activated carbon adsorbs toxins (styrenes, heavy metals, etc) its use in aquaponics would be highly desirable.

Toga....a few questions....

• Does it work in highly stocked aquaponics systems? (as distinct from very lightly stocked aquarium tanks).
• How do we use it?
• How much do we need for a given volume of water?
• Once it's no longer effective (that is, that it's soaked up all the impurities), can it easily be re-activated at the backyard level?
• What's the most cost effective way to buy it? Any local sources that you're aware of?

Toga, thanks for introducing the subject. Like many other people, no doubt, I was aware of the use of carbon filters in a variety of situations (fish-keepers, distillers, etc) but I'd never thought much about its use in an aquaponics context.

Gary

[jobney]

From what I've read before it also removes chelated iron.

[GaryD]

Hi Jobney,

That wouldn't bother me. I'm happy to run separate loops for fish and growing systems.....and to dose the plant system with anything that it needs. That allows me to avoid the compromises and to provide the optimum conditions for both fish and plants.

Gary