pH control using CO2

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grimreaper
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pH control using CO2

Post by grimreaper »

Does anyone use CO2 as a means of controlling the pH in a fish only tank (no plants or substrate) i.e Using a pH controller / CO2 cylinder set to a specific pH?
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smithrc
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Post by smithrc »

what sort of PH do you have at the moment and what are you looking to achieve?

I've only ever used CO2 system on planted tanks - and after 2 problems I swore I would never use them on a tank with fish in it that I wanted to live :wink:

It was a great way of altering the PH - all the pay down to a PH of about 4 when it went wrong (the system didn't have a controller)

considering the post is in the general care and breeding section of zebrapleco - I'll go with the assumption that your considering using it on a zeb tank - I'd urge you not to risk the fish.

If you are adding co2 to a zeb tank - the water movement and added oxygenation that they like would dispurse the co2 very rapidly. the controller would have to add a lot of co2 to try and alter the PH.

PH isn't as important I used to think - and fish are not as fussy about it as we are.

When I had a PH crash and the planted tank, it was SO full of CO2 the fish were dying - I saved 3 plecs by simply picking them up as they were 'unconsious' on the bottom of the tank, and putting them into a different tank... no "PH shock" no "temp shock" just lively fish 20 mins later.
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grimreaper
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Post by grimreaper »

Hello smithrc
Thanks for your response. I'm am looking to reduce the impact of increased ph during water changes. My system automatically changes 75% of the tanks water every 12 hours. I live in a very soft water area and the mains pH, if not controlled by South West Water would be low so they add aluminium sulphate to the mains fresh water to increase the pH. Where I actually live the pH from the tap is 7.9 /8.0 pH my tanks are at 6.7pH so there is a big change every 8 hours. I use CO2 to maintain the pH of a calcium reactor for my coral tanks at 6.5 pH. I did not want to buy some expensive kit to find there is a problem. I run a large tank as a reservoir that is kept at 30 Deg C and filled automatically via the mains. Water is pumped from this large tank every 12 hours into my fresh water system. The fish tanks water then overflows into a drain. My aim is to keep the pH of the large tank at 6.7 pH.
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smithrc
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Post by smithrc »

75% every 12 hours!!!.... that cant be good. :shock:

All you'll do in a situation like that is cause a major PH swing from the tap PH to the desired PH every 12 hours - now that sort of instability will cause a lot of stress...

Why do you do it so often?
If I had an auto system (and I'm planning one that I can move from tank to tank) I'd still only change 25-30% every couple of weeks...
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grimreaper
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Post by grimreaper »

"All you'll do in a situation like that is cause a major PH swing from the tap PH to the desired PH every 12 hours - now that sort of instability will cause a lot of stress... "
That's why I want to control the pH. I want to keep the tank water as clean as possible.
I am not in a position to set up de-nitrification filters yet so I do massive water changes
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Post by smithrc »

you have no filters?
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grimreaper
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Post by grimreaper »

Yes, The fresh water system has sponge filters to do the first part of the nitrogen cycle. I then need a de-nitrification filter to complete the cycle and have fresh water with no nitrate. Once I have set up this filter I can reduce the water changes but I still want to control the pH. That does not mean any specific pH but the ability to maintain or change it.
My origional post was to ask "Does anyone use CO2 as a means of controlling the pH in a fish only tank (no plants or substrate) i.e Using a pH controller / CO2 cylinder set to a specific pH?" It seems no one does so I might go ahead and buy the kit and then do some experiments when I have time.
Thank you for your help smithrc
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Grim
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Post by eklikewhoa »

I wouldn't use co2....I would rather use a ageing barrel and set the parameters there first and letting it stabilize before doing the water change.


with co2/controller anything can go wrong at any given time and cause either a crash or drastic fluct in params killing everything.
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grimreaper
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Post by grimreaper »

I appreciate your concerns eklikewhoa but I have run the same system on a marine calcium reactor for a very long time with no problems. If you buy good quality equipment it is very reliable. Many years ago I bred many thousands of Discus. I had a very large "pond" which I used to condition water with peat. I realy wantedto know if anyone had used CO2 to control pH in a fresh water system
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John
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Post by John »

grimreaper wrote:Yes, The fresh water system has sponge filters to do the first part of the nitrogen cycle. I then need a de-nitrification filter to complete the cycle and have fresh water with no nitrate.
Something like this? :

http://www.aquarientechnik-gralla.de/es ... ilter.html
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John
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grimreaper
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Post by grimreaper »

Yes John
In my opinion de-nitrification is very straightforward if you go about it the right way. You need a container that has an inlet and an outlet for tank water. It must be air tight and be filled with a large surface area filter media. A pump to circulate water within the container is recommended. I have an Aqua medic one and a home made one (25 litres capacity) You will also need an ORP meter that can switch on a valve at a specific millivolt setting. I use Aqua-Medic ORP controllers on my shrimp breeding system and my coral system. They are both set to -180 mv. (minus 180 mv). The ORP probe is fitted in the container and monitors the voltage within the container. When the voltage in the container drops to -180 mv the meter switches on a valve and system water containing nitrate is pumped into the container. The outlet from the container goes back to the main system but without nitrate present. As the voltage inside rises due to the system water entering the meter switches off and the cycle repeats itself. These de-nitrification systems need to be fed, that is the bacteria on the filter media, with a carbon source. Cheap Tesco Vodka works well, it must be cheap. It is dosed in my filters with a dosing pump and delivers about 2 ml of vodka per 24 hours. This is what I will make when I have time so I will be able to reduce water changes
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Post by smithrc »

good greif man... you have some very advanced equipment - sounds like you know what you want to achieve and wont have a poroblem doing it...
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Post by grimreaper »

Hello smithrc
Thank you but if you could just tell that to my Zebra's it might help :wink:
I have to use these filters on my shrimp system because of the volume of water and the fact that to raise significant quantities of ornamental marine shrimps you need to massively over feed the larvae. I am not doing a good job at the moment with regard to water stability for my Zebras but I hope to rectify that soon as I'm getting too old and tired to run my very large shrimp system and once it is shut down I will concentrate my efforts on Zebras.
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Grim
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