Carbon in a tank with plants ( adding fertilizer) ???

[Magnum Man]

I was just looking at the current TOM entry’s, and 1st off this tank looks amazing…

But this got me thinking, if you were adding a fertilizer for your plants, while running carbon in your filter, wouldn’t the carbon absorb most of the added fertilizer???

I’ve actually gone from using “a ton” of carbon, to not using any and my tanks and fish are doing great, makes me wonder if that was wasted money over the years…

I know some plants will not thrive, without the addition of fertilizers… I don’t add a fertilizer anymore… and have had to pick and choose plants that would thrive on the current level of fish waste, so I understand, that most well planted tanks are going to need fertilizer, but wouldn’t it be counter productive to add fertilizer to a tank, that you are running carbon in???

 

[Colin_T]

yes carbon will remove plant fertiliser.

 

[Magnum Man]

… my understanding of carbon, is that it’s like a sponge, so it’ll only hold so many “impurities” ( which could be fertilizer, or medications ) so it could be filled up with fertilizer, and not absorb anything else, and a second dose of fertilizer, then may be available to the plants, if it’s added regularly, if the carbon has already absorbed what it can hold, but that begs to question, why use carbon in a planted tank, in the 1st place, if you’re adding fertilizer???

 

[Sparx]

You raise a valid point there Magnum Man! I’m actually keen to find out opinions of this.
My tank has always had activated carbon, and I’ve only introduced plants in the last month or so, never had live plants before so quite new to it. When we were looking into adding plants the guy in the store didn’t even ask if we used carbon, but did recommend the supplements we use.
I didn’t even realise this would be a factor!
But I can say for certain that it hasn’t caused any problems with the plants that I can see, in fact they’re flourishing to the point I’m having to trim them down.
I just wonder if it’s causing the carbon not to work properly

 

[Magnum Man]

Actually, thriving plants, can do some of the work, that your carbon used to do…
@Sparx … BTW… your tank looks amazing…

I suspect, your carbon is likely filled, I believe it still acts as a media for beneficial bacteria… but a coarse sponge, would likely easily replace the carbon

 

[GaryE]

Carbon dates back to the era when water changes were seen as disrupting the balance of a tank. You could smell those tanks when you entered a room, and activated carbon could keep the stink down. But the hobby being what it is - carbon is not cheap, so it is still suggested by many stores. I haven't used it in filtration since before computers had appeared in homes...

 

[Sparx]

Actually, thriving plants, can do some of the work, that your carbon used to do…
@Sparx … BTW… your tank looks amazing…

I suspect, your carbon is likely filled, I believe it still acts as a media for beneficial bacteria… but a coarse sponge, would likely easily replace the carbon

Thank you I am really pleased with the way it looks.
But that is good to know about the plants doing some of the work, I wasn’t aware of that.

 

[Magnum Man]

I guess this is kind of my Caffeine subject of the day…
( things I think about, while watching my tanks, and drinking my morning caffeine )

 

[TwoTankAmin]

I know there is a lot of misinformation online re carbon use. But in relation to pants and ferts here is what Tom Barr wrote in 2011 on his forums in a thread re this issue.

Amano uses it, then after it's spent, it becomes biomedia.
Same could be done with Zeolite also.

I've used both on occasion.

Not needed though.

https://barrreport.com/threads/carbon-in-a-planted-aquarium.8789/

Dr. Tom Barr is a world renowned aquascaper, author, and aquarium plant enthusiast. He holds a bachelor’s degree in aquatic biology, as well as a master’s degree in botany, and a PhD in plant sciences. Tom has been keeping aquariums for over 40 years, with planted aquariums being his focus since 1989. He is best know for his research on plant nutrients, and the development of the Estimative Index (EI) method of plant fertilization.

The above is from an Aquarium Co-Op vid. Oct. 2021. One has to be a member to view it and I am not. But the info above can be seen by anybody: www.youtube.com/watch?v=SY7VtmqLMi8

 

[MaloK]

I'm not a plant expert by any mean. And also keep in mind that I'm running nano tanks.

But if I was fertilizing a well planted aquarium at full dose every week. In addition of water changes I would still run 1 teaspoon of fresh carbon per gallons of water 1 week per month and not fertilize during that week. To make sure that there is no buildup of unknown unused nutrients in the water.

At the moment I fertilize less than that and still run the carbon once a month, on top of my filters, when there is no carbon I put a piece of poly-wool that I rinse from time to time.

 

[StevenF]

Carbon can absorb some of the nutrients in the fertilizer but how much depends on the ingreents in the fertilizer. Bfut for the most part carbon is irrelevan because PH and KH have a much bigger effect on fertilizer. KH in your water will react with most sulfide ingredient ion many fertilizer forming insoluble metal carbonate which plants cannot use. Many people have had success with commercial fertilizer if they does them about once every other day. The frequent dosing is needed because the fertilizer is bing destroyed by the KH. PH and affects iron solubitlty. From my own experiments you only need to dose once a week if your water has no carbonates and has a PH of 6.5 or less. Or you can use cheated fertilizer ingredients and iron DTPA once a week at a PH of of up to 8 with carbonates.

 

[Nells250]

I looked up "Dr. Tom Barr" and now I have a bunch of stuff to look at!

 

[powerdyne6]

Lol this has me thinking about my tank….

Can someone tell me if the 5 pre filters in the Oase biomaster350 contain carbon? By my reading I think they do.

I have been using Seachem flourish for close to a year now. If they include carbon prefilters I guess my fertilizer has been doing nothing.

 

[Magnum Man]

Or more likely, the carbon becomes inert, after a dose or two of fertilizer

 

[powerdyne6]

Or more likely, the carbon becomes inert, after a dose or two of fertilizer

Is this a thing?

If so then I guess all is good