4 years ago #1
Guest
Guest

Does an activated carbon filter ever change pH?

Our tap water seems to be changing pH when it goes through an activated carbon filter. It's pH is 7.4 when I put it in the tank and 8.4 the next morning! There's nothing in the tank but water, gravel, and a filter with activated carbon.

A completely different tank & filter produced the same pH change. Water sitting in a tank without a filter did not change pH, at least not enough to notice in 12 hours.

The water is from a private well that has a lot of minerals in it. It is treated with a water softener before it gets to the tap, though I could use untreated water also.

I want to keep a few guppies in a 10-gallon tank. Can I toss out the carbon filter? If not, how should I handle water (or filter cartridge) changes? I'm worried that the pH is going to yo-yo every time I change some water and will shoot up when I change the carbon.

Answer
4 years ago #2
johnarthur
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Chances are, the problem is with the water softener. I believe softeners remove the minerals that are needed to buffer the pH. Activated charcoal stays that way for only a few weeks.

Fast changes in pH or other water parameters stress the fish, so you should avoid them if possible. As an aquarium matures, the pH generally gets a bit lower. In case you were not aware, pH is measured on a logarithmic scale, so a change of only 0.1 is quite significant.

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4 years ago #3
balkenhol
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It was worth a try, but no. I refilled the tank with un-softened well water last night. The pH changed overnight exactly the same way.

One of my filters is new and the other is a hand-me-down. I haven't double-checked yet, but I'm pretty sure they both did the same thing.

I could use the filter without the carbon in it (pH 7.4) or I could pre-filter all water before using it (pH 8.4). Which would you recommend?

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4 years ago #4
mjrkiller308
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heres a good idea also mgf youcould age the water so right when u are doing water changes u replace taken water with water that has beneficial bacteria in it and its way closer to ur tank water than any other water besides ur tank water. take a garbage can or a 20 gallon tote container and fill it with water. sitck a heater in there and set it for same temp as ur main tank and put an airator in there also. do this aout 24 hrs b4 your next water change and the water will be ready then, i like to keep some ready 7 days a week u never know when u get a sick fish or need to transfer fish for bad behavior or nething its nice to have aged water justsitting around kindof like extra tanks lol gl hope this helps

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4 years ago #5
johnarthur
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Activated carbon will absorb some minerals, and that could change pH. You may also want to test for the presence of ammonia. It's a compound of one nitrogen ion and either three of four hydrogen ions. Ammonia is a reactive compound, and hydrogen ions can lower pH.

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4 years ago #6
Mr. Carbon
Guest

Yes, activated carbon can cause a pH excursion that can last for several days or weeks. Since an aquarium has a relatively small volume of water, the pH rise is more pronounced than in large commecial or industrial activated carbon water filter systems. Typical acitvated carbon made from coal has a pH of 8.5-10 (ATSM pH test method). The activated carbon itself can act as an ion exchange type media and that can contribute to pH rise. One can buy acid washed or neutralized activated carbon or you can try to wash and soak the carbon for a few days before you put into the aquarium.

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4 years ago #7
johnarthur
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Thank you for that explanation. I didn't know that activated carbon can produce ionized minerals. Quick changes in pH are harmful to aquarium fish.

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3 years ago #8
Angela
Guest

I have been using an indian herb which turns the water red when boiled. When I use filtered water it goes pale yellow. when I used tap water, which does go red it turned yellow when I added lemon so that says something.

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3 years ago #9
Balkenhol
Guest

Sorry guys, that was a red herring. I took the filter cartrige out and got the same pH change. Seems to be the airation from the filter-mechanism's waterfall. Put a bubbler in there, without any of the filter stuff, and the effect is the same.

I'm guessing that I might have a lot of disolved carbonate in my well water. A higher concentration of CO2 in the attmosphere is making our oceans more acidic. Seems reasonable that having carbonate bubbling out as CO2 would make the water more basic.

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3 years ago #10
johnarthur
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The herb is probably catappa leaf, which is also called Indian almond leaf. The leaf produces tannins that gradually soften the water and lower pH. Leaf litter does the same thing in the Amazon basin where several aquarium fish species originate. Leaves gathered from the wild near industrial or agricultural centers may be contaminated with herbicides, pesticides or other toxins. Commercial products may be safer.

When a dry catappa leaf is placed in an aquarium, it lightly stains the water yellow. Peat moss and driftwood do the same thing, but the stain usually goes away with a few partial water changes. Boiling likely removes most of the tannins quickly and turns the water a darker brown or red. Lemon juice contains acid, and that's probably why it changes the color of the water. Please don't use lemon juice in an aquarium.

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3 years ago #11
Angela
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sorry, I was just looking for a solution to why the water changed colour depending on which type of water I used with the herb which has a very long name. I came upon your site looking for an answer. I promise not to put lemon juice in the fish tank ever.

Thanks,
Angela

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3 years ago #12
johnarthur
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If you wish to, you're welcome to join our forum. It's free, and we're not selling anything.

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3 years ago #13
Noman
Guest

do you have any idea why the ph goes low when it passing thru acid wash activated carbon media. we are using municiple water for the treatment of mineral water plant we are comenly facing problem while the infeed of A/C filter is 8.4 ph and outlet nearly 6.75-7.3 ph, after several time passes the effect in the ph at outlet become same, in this timing we are facing ph proble, that's y only the way to reacidification of the media every weekly, please define why its happening.how can we control?

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2 years ago #14
RobSkeezy
Guest

I happen to know that activated carbon is "activated" with hydrochloride or sulfuric acid in many industrial cases. It's just part of the process to make all the holes in it. Allot of the companies just rd urn the carbon after the acid bath. I am not sure of the neutralizing process used other than that or how affective they are. It is certainly something to keep in mind a d some food for thought. I'm typing on my phone or I would write a more specific post.

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2 years ago #15
johnarthur
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The acid bath seems feasible, but the carbon probably gets a good rinse after that. I always thought its final stop was a vacuum oven. Of course that would not clean out the microscopic holes; it would just make the stuff really dry. Anyhow, thanks for the information.

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2 years ago #16
WeeKian
Silver Member
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Thank you for your kind answers and response about Activated Carbon Filter.

On 12th March 2013, Tuesday, I was advised by my experienced friend Jack Lee of Singapore, of a very good Arowana Fish Farm.

When he came over to my Aquarium in Shenzhen, he saw that I was putting a bag of Activated Carbon in all of my sump tanks filtration, and advised me to REMOVE ALL OF THEM.

Here were his reasons.

Activated Carbon absorbs nutrients in the water, although he didn't expand on that. This appears to be my homework

Next, he expands, Activated Carbon is only useful when you want to absorb excessive MEDICINE, CHEMICALS, that we tend to put in unnecessarily. Usually, it'll be more than enough to put the Activated Carbon bag into the SUMP TANK, for 1 to 2 days.

While I was in his fish farm back in October, November of 2012, I did noticed that there wasn't any Activated Carbon used in his Filtration Medias.

What I saw was just normal White Wool Filter Media, KOI Mats (BLACK SPONGE - SQUARE), and BIO-RINGS, nothing more...

By the way, he is taking care of more than 3000 over fishes in his fish farm, and I believe in what he says

Besides he has over 20 years of Asian Arowana Experience...

Hope this is useful for all readers out there, and please do use Activated Carbon only when necessary...

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2 years ago #17
PensFan85
Guest

I completely agree. I live in an area with a less-than-steller natural water source.. I have had many issues with ph and nitrate levels in my nano's as well as my 225gl. I thought this was due to the weak water treatment by the city (which may still not be the best). After a brilliant friend at oddball pets in Pittsburgh, Pa brainstormed and studied test results by my city (neighboring pittsburgh) as well as my own test results, he asked me to take out the carbon cartridge in my filter. I put in a samll carbon bag (two for my 225gl) for no more than 24 hrs after a large water change (more than 15%). He tried explaining it all to me but 90% of it was over my head. I could not believe the difference. Now im at the point where I only use carbon when there is a spike in any chemicals,medications, etc. My fish and plants have never seemed healthier.

Its nice having an aquarium store nearby that is more concerned about your experience and tanks health than making an extra dollar in the short term. Ill never shop anywhere else.

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2 years ago #18
GarryJ
Master
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Hi PensFan85

You may not be aware that this post is 2 months old.

Just look at lost post top right hand corner.

Cheers

Garry

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2 years ago #19
Freshwater enthusiast
Guest

I am going to remove one activated carbon pillow out of two that are placed in my bio filter.I just lost about 10 beautiful and expensive discus.I don't know what caused it. ph is 7.0 which i reduced using commercially available powder.I am not new to aquarium hobby as i have petted 100's of species in more than a decade. Water is crystal clear.Can it be stress caused by 30 cm silver arowana?or this new driftwood that i placed in the tank which took 10 days to sink(it was not placed in the tank,instead it was placed in a huge bucket with lid closed and fully submerged inside water).I thought it would be good environment for discus.Bottom of tank is white sand.No over-feeding.Instead gave them 3 kind of foods.Frozen bloodworms,jbl sinking type,tetrabits.My tank also have 2-motoro stingrays,1 penny synodontis,1 sailfin pleco,1 clown peckoltia pleco,2 kuhli loach,1 featherfin synodontis.Is it aggression?some disease?(one discus died of hith out of ten,most of others had wounds(previuosly small which grew large rapidly and they lost their lives within 2-3 days of wound-visibility),is it some body mucus depletion or discus plague?or depletion of mucus through stress of living with arowana plus disease?Or combination of everything including less acidic water(high ph)?????I was researching for answers.Can someone help.Here i can see some old-timers.This many challenging factors make fishkeeping an interesting hobby.If i graduate with discus,i can claim my territory in freshwater fishkeeping territory like a flowerhorn,but one thing i will not do is, bully other hobbyists like it.I will appreciate your experience sharing.bye and take care.

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2 years ago #20
Mr. Carbon
Guest

An aquarium application does not need acid-washed activated carbon. In the USA, Norit (now Cabot) Lignite granular activated carbon is sometimes sold to the aquarium market and as part of the lignite processing to reduce total ash, the carbon is treated with acid but it is not really acid-washed product. If one buys Chinese aquarium carbon (note - all coal pellets are from China), it should not be acid-washed (if it is acid-washed then hydrochloric acid is typically used and it should have been water rinsed to remoce excess acid) - the acid-washing is not part of activation but rather a process to reduce acid soluble ash including metals.

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1 year ago #21
ste70
Guest

my experience with discus is that they rarely do well when kept with other fish that are bigger faster or bigger mouthed, they are shy fish and fussy eaters, having small mouths they do not always get a lot of food if other fish get in there first, I would only keep discus with small tetras generally and definitely not loaches

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1 year ago #22
Rick
Guest

Well water is most likely high in co2. Check it with a co2 test kit. As the co2 gases out from airiation the ph will rise. Normal chemistry

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1 year ago #23
morris
Guest

our RO water has a high PH 9-9.5. Can I drop the PH to 7.00 -8.5 PH with acid wash carbon for drinking water??

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1 month ago #24
tamer khider
Guest

hi every body
iam as sales engineer
i supllied indodisn carbon to the client before potable machine
to remove chlorine before ozone
still reading for chlorine
i think it was due to raising PH
raising ph is good to keep the chlorine in hypochlorite radical

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