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Use of Activated Carbon, Purigen, etc.

jaypeecee

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21 Jan 2015
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Bracknell
Hi Folks,

I'm trying to get an idea of how many UKAPS members use products such as those above to prevent build-up of dissolved organics. Judging by the lack of threads that mention this, I get the impression that control of organic compounds is handled (almost) exclusively by tank maintenance and regular water changes. Would that be a fair assessment? If so, what has changed in our hobby to bring this about?

JPC
 

Garuf

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30 Oct 2007
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Copenhagen
I use both carbon and purigen. The reason is solely to strip any tannins from my wood heavy scape, anything else is either a positive or a negative dependent on phase of the moon.

I have it in my understanding neither effect ferts levels and the idea they do is tradition over fact.
 

KirstyF

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25 Jul 2021
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Kidderminster
I use purigen for water polishing just because I can, but have two filters and gyres so don’t really need to worry about reduction in flow.

I wonder whether some folks choose maximising flow over adding more ‘stuff’ to filters perhaps, though that is just a personal view.

Also, from the planted tank perspective, if folks are doing regular water changes to re-set ferts and/or as good practice to reduce/minimise algae anyway, then perhaps they don’t feel so strongly that the ‘stuff’ is necessary.

I suspect that for some planted folks, even the use of ‘standard’ filter media is becoming a much lower priority these days. ‘Scrunchies, sponges, whatever is cheap and to hand is good enough. The plants do the rest’ is certainly not such an uncommon approach on this forum at least!
 

erwin123

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4 Mar 2021
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Singapore
I use purigen because its reusable and since it turns brown after a few months hopefully its absorbing something that the fine filter floss can't catch (i.e. i put it after the fine filter floss).

I'm running at 14x flow so I have some headroom to use fine filtration which may reduce the flow.

I had 4 bags of free carbon with my Fluval filters. After I used them up, I didn't bother to buy new ones and frankly could not tell the difference.
 

jaypeecee

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Hi Folks,

Thanks for your replies.

I am going to ask this same question on other forums. Then I'll see if any conclusions can be drawn.

JPC
 

Zeus.

Fertz Calc Meister
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1 Oct 2016
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Yorkshire,UK
I like Purigen - except for the price, of course.

I really dislike the term "polishing of water" because it's a meaningless phrase invented by someone who didn't really understand what these types of resins actually do. They use it, the water gets clearer but no one know why, so they invent a phrase based on some kind of metaphor, like polishing furniture.

In fact Purigen, like activated carbon has an electrostatic affinity for organic Nitrogen compounds. Have a study of the thread Can Purigen Strip down useful nutritients? for more information.
Some of the links may have died, the thread is about 4 years old.

There are also some similarly old threads floating around discussing regenerating the Purigen to save money.

At the end of the day though frequent large water changes does what all these resins do, so I stopped spending money on these.

Cheers,
Clive
 
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I use activated charcoal in one of my filters as the bogwood in the tank colours the water too much for my liking.
 

KirstyF

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😂 Good old Clive!!

He’s right of course! though in fairness, ‘I use purigen as it’s electrostatic affinity for organic nitrogen compounds floats my boat’, is a bit of a mouthful! 😉😂
 

Midwife

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8 May 2021
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Down south
I get the impression carbon is a waste of money as Its gets spent in a day or so. Especially the cheap stuff. If I have Purigen knocking around I use it in new setups or floss otherwise more water changes. Myself bare bottom tanks or a thin layer of substrate are growing on me rather than deep beds.
 

DogTailRed2

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23 Sep 2021
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UK
One thing to consider with purigen is the bleach to reactivate it is very hard to get in the UK.
 

dw1305

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UKAPS Team
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nr Bath
Hi all,
easy to get being sold in most super markets and has no additives.
I know what it contains:
It contains 1% sodium hypochlorite (NaOCl) and 16.5% sodium chloride (NaCl)
But I've never been a Purigen user and I don't know if that it is a high enough concentration of sodium hypochlorite.

cheers Darrel
 

jaypeecee

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Hi Folks,

Thanks for all the feedback.

So, other than removing tannins to prevent brown-tinted water, it seems that activated carbon, Purigen and similar products get the 'thumbs down'.

Thanks again.

JPC
 

jaypeecee

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I am going to ask this same question on other forums.
Hi Folks,

As it turned out, I didn't need to ask the question. The answer was immediately obvious. Here's an example from one post:

"Use it, without a doubt, especially at startup. What if you don't do enough water changes? What if you have a high organic load? What if you have an insufficient bio-filter in terms of plants and bacteria? It's just another way to keep your tank cleaner of organics. You will have to change it when necessary to keep up it's effectiveness, but there are plenty of reasons to use it". In this instance, "it" refers to activated carbon.

This is also well worth reading:


JPC
 

John q

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Lancashire
One thing to consider with purigen is the bleach to reactivate it is very hard to get in the UK.
Most cheap thin supermarket bleaches contain 1% Sodium Hypochlorite, there's mixed opinions as to how good 1% strength bleach works. We have threads about it.

You can buy Sodium Hypochlorite 4.5% strength thin bleach fairly cheaply, unfortunately the £4.99 shipping price bumps up the total cost a bit.


 
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PARAGUAY

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13 Nov 2013
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Lancashire
I think both products are good, price aside , and purigen seems good value because of as said above but it's now known activated carbon is not a necessity as was thought years back. I use purigen now and again but wouldn't fret if run out. If you need to remove meds or have a soil disturbance it's handy to have carbon in the cabinet. But water changes are the way to go most of us think
 

Wookii

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13 Nov 2019
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Nottingham
I used to use Purigen, but like many products in the aquarium trade, it’s a bit of a ‘faith’ product. We have to take it on ‘faith’ that it is actually capturing organic compounds.

Ultimately we don’t really know if it truly is capturing organics as we have no way to measure exactly how much it is capturing, relative to those generated by the tank.

When I started adding botanicals to my tank to actually increase the tannins and other beneficial organics acids (that some folks are actually using Purigen to try and remove), I stopped using it as it would have been counter productive.
 

jaypeecee

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Ultimately we don’t really know if it truly is capturing organics as we have no way to measure exactly how much it is capturing, relative to those generated by the tank.
Hi @Wookii

For a couple of years, I have been investigating any correlation between dissolved organics and oxidation-reduction potential (ORP) in my tanks. Based on these measurements, there certainly appears to be a strong correlation between these two water parameters. In a pristine tank, ORP typically measures +400mV to +450mV in the water column. I took a sample of this water a few weeks ago and sent it to a test laboratory where they measured a TOC* of 2.2mg/litre. I hope to get the water re-tested sometime soon.

I should add that ORP is used as an indicator of water purity in a variety of fields. I'll try to pull together some articles and scientific papers on this fascinating topic if anyone is interested.

* TOC = Total Organic Carbon

JPC
 
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