# pH problems ?



## david f (Mar 24, 2006)

Hi there People,

My name is David, I am 28 years old, from New Zealand and I love my country. I am one who likes to browse through all the pretty photos of those lovely aquariums and read what you people post, I hope thats O.k.
"My problem is the soft water that flows down the river into the large 1 million litre water tank which then flows to the taps at our house".
(pH7 gh1 kh1). I then modify the water using calcium carbonate,baking soda,epsom salts and potassium salt which ends up gh4 kh4 and pH 8.0-8.2.
thats no so good though. So, I recently realised that if sphaghnum peat moss is used pH falls back at 7.0 'sweet as'. I'm not sure as yet if the alkalinity is holding up though, because my pH rises gradually through out the day from pH 7.0 early morning right up to about pH 8.0 late afternoon.I know this is normal in nature but is there a way to stabilise these pH swings. 

I would appreciate any suggestions,Thanks.
I would have liked to have sent a picture of my tank,but not to sure how to as yet,


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## primal (Jan 30, 2007)

The baking soda (and maybe the calcium carbonate) are going to buffer your system, causing the higher pH. You might want to try leaving out the baking soda and see if that helps. Its completely pointless to add baking soda, then add something else to negate its effects.


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## Rummynose (Feb 4, 2007)

*pH problems*

Hi David,

Since your pH is higher in the afternoon, I would say the high pH is from photosynthesis. In nature, as you stated, high pH values are very normal at the brightest part of the day when photosynthesis can quickly strip all or most of the CO2 from the water.

My tank is a 55 gallon Diana Walstad type set-up with the exception of modest amount of CO2 injection. I use a two litter soda bottle with a home made reactor using the Nyberg Method for a reciepe. Before this small amount of added CO2, my pH was around 7.7 - 7.9 . Now my pH averages 6.8 - 7.0 with CO2 levels averaging 12- 15 ppm. Keep in mind that this is not a high tech pressurized system that adds a frightening amount of CO2 that can wipe out every fish on the block. Its just enough to keep the pH were I want. And my plants love it!


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## DataGuru (Mar 11, 2005)

You don't want KH at 0ppm.

all my natural planted tanks have crushed oyster shell added to the soil, KH out of the tap is 120ppm, pH runs in the high 7s. my plants and fish do great.

If it were me, I'd stick to your buffered up water and add crushed coral or crushed oystershell.

Diana has some recommendations for hardness in her book, tho I don't remember off the top of my head what they are.


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## david f (Mar 24, 2006)

Thank you, Primal

When using a water bin for trial runs I usually add calcium carbonate or oyster shells,the baking soda is an alternative,but the word 'negate' that you used I don't quite understand, I will find what that meaning is though.


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## david f (Mar 24, 2006)

Thank you, Rummynose

I did not know that carbon dioxide CO2 has such an affect on pH readings.
I wonder if late afternoon pH rise is causing the acidic and base reactions to become unbalanced?. due to a lack of CO2.


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## david f (Mar 24, 2006)

Thankyou, DataGuru

I am still wondering if I should use calcium carbonate or baking soda to keep my water buffered.It is good that your fish are well.


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## david f (Mar 24, 2006)

Thank you all,It sounds like I'm on the right track.


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## ed seeley (Dec 1, 2006)

DataGuru said:


> You don't want KH at 0ppm.


I run all my tanks at 0dKH. With pressurised, DIY and no CO2 in various different tanks. I've never had a problem.

pH usually settles out at about 5.5 to 6 (lower in the added CO2 tanks)

David, your tap water sounds like a god-send for soft water fish like tetras and leave it well alone! I have to use RO water to get soft water! You Kiwis sure get all the luck, though maybe not in the cricket yesterday, you should have beat those aussies!!!!!


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## primal (Jan 30, 2007)

David, I just meant that there is no sense in adding baking soda, which will raise the pH, and then add peat moss to lower it back down. As you know, the baking soda will buffer you water, so adding peat moss is only a very temporary solution, since the acid from the peat moss will quickly be buffered by the baking soda.

Lessening your buffering capacity, if I'm not mistaken, will allow you to have a lower stable pH. Just experiment with adding less "stuff" to your water. Besides, the less you add to your water, the easier and cheaper your tank is to maintain!


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## Rummynose (Feb 4, 2007)

Hello David, 

pH and CO2 have a very strong relationship with each other. When carbon dioxide reacts with water a mild, unstable acid is formed called carbonic acid. The greater the amount of CO2 in the water the lower the pH. If you have any doubt perform this smiple experiment: fill a small clear plastic bag about 1/4 full with your aquarium water. Now add several drops of a pH indicator such as Bromothymol Blue. Put enough drops in so that you can clearly see the color. Gently mix and observe the results. Now squeeze as much of the air in the bag out as you can. Next, using your own breath, fill the bag up with air, seal and shake it for 15 seconds. Now check the results. You will most likely see drop in the pH reading. What has happened is the increased levels of CO2 in your breath reacted with the water forming carbonic acid thus lowing the pH. If you were to aerate the water with an airstone, the excess CO2 will disipate and the pH will return to its previous level.

As far as having 0 KH levels in your aquarium, I would be very careful. Carbonate hardness acts as a buffer. In other words it helps keep the pH stable. If KH is not present you can experince very drastic changes in your pH. KH levels of 3-4 keeps things on the safe side for the fish which may suffer from a pH crash.


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## david f (Mar 24, 2006)

Thank you, ed seeley

Most of the fish on sale here are softwater species,probablly well suited to our water. there is also a small natural water spring a little drive from here,it is very clean drinkable water with pH5.5 kh 0 gh 0. I have uesd it before, but it is uneconomical to travel. 'As for that Cricket, if it's one of those days I just flick the channel over' Cheers for your advice.


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## david f (Mar 24, 2006)

Thank you, Primal

I will defenitly give your advice a bit more thought.
'Negate' an interesting word,I understand what you were meaning by it now.
I'm not sure if I'm right here, but by keeping gh 4 kh 4 pH 7.0 ,that's with the peat moss included,acidic and base reactions sould remain stable if the water is in a water bin. But when there are other things such as plant photosynthesis,bacteria,fish poo's,decompostion etc,things start to change a bit, including my pH readings.


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## david f (Mar 24, 2006)

Thank you, Rummynose

, You have been very helpful at explaining the interactions of CO2,pH and plant photosynthesis.The loss of CO2 or not enough has been especially helpful.


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