Ph KH C02

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Hi Riccardo1976

I am not experienced enough to provide a 100% safely answer to your concerns but I can assure you raising you Kh will ultimately allow you to better control your Ph level – between water changes there is nothing stopping you maintaining a ph of 7 with a Kh of 8

However I understand your concerns although my ph started at 7.6 @ 3.36dh. Slightly better then yours.

First what will your fish be happy? In higher PH in understand the range i.e 6-8 (my pleco). Fish can handle ph shift in small amounts over a long period of time!!! 0.2 every 12hours for example

I would not change you tank kh, I would slowly raise your kh at every water change.
I would also expect you will continue to add co2 at a reduced rate – This will bring the ph down over time in your main tank. Remember a 20% water change may only rasie your ph 0.1 depending on how much your raise the kH. So your tank will change slowly – not rush it – I am not.

Remember at the same time you are planning to inject C02 so this will continue to bring your ph down (slowly) until you reach the level you require - I also think you should start with a low level target of C02 and increase it with time. Say 5mg/l then 8mg/l ect.... up to 18mg/l see what happens to your plant growth. – I currently have just under 8mg/l of co2 and my tanks is full of bubbles J t

Rising your kh does raise your PH keep an eye on your fish for signs of sore spots stress ect.. but once you have control of your Co2 injection your ph will stabilise. Although I now have concern regarding leaving the co2 on all night – this will ensure the ph does not rise to high during the night. I will obtain a PH controller and leave the unit on all night.

Also

Start to log you ph over a 24-hour period – this will show you just how much your ph can change normally you may find a 0.4 deference . Plus it gives you some great data for when you start to add co2.

You must become in control of your tanks water parameters! So start taking some reading and takes control… I have and if feels greatJ
 
Ob1 said:
Hi Riccardo1976

I am not experienced enough to provide a 100% safely answer to your concerns but I can assure you raising you Kh will ultimately allow you to better control your Ph level – between water changes there is nothing stopping you maintaining a ph of 7 with a Kh of 8

However I understand your concerns although my ph started at 7.6 @ 3.36dh. Slightly better then yours.

First what will your fish be happy? In higher PH in understand the range i.e 6-8 (my pleco). Fish can handle ph shift in small amounts over a long period of time!!! 0.2 every 12hours for example

I would not change you tank kh, I would slowly raise your kh at every water change.
I would also expect you will continue to add co2 at a reduced rate – This will bring the ph down over time in your main tank. Remember a 20% water change may only rasie your ph 0.1 depending on how much your raise the kH. So your tank will change slowly – not rush it – I am not.

Remember at the same time you are planning to inject C02 so this will continue to bring your ph down (slowly) until you reach the level you require - I also think you should start with a low level target of C02 and increase it with time. Say 5mg/l then 8mg/l ect.... up to 18mg/l see what happens to your plant growth. – I currently have just under 8mg/l of co2 and my tanks is full of bubbles J t

Rising your kh does raise your PH keep an eye on your fish for signs of sore spots stress ect.. but once you have control of your Co2 injection your ph will stabilise. Although I now have concern regarding leaving the co2 on all night – this will ensure the ph does not rise to high during the night. I will obtain a PH controller and leave the unit on all night.

Also

Start to log you ph over a 24-hour period – this will show you just how much your ph can change normally you may find a 0.4 deference . Plus it gives you some great data for when you start to add co2.

You must become in control of your tanks water parameters! So start taking some reading and takes control… I have and if feels greatJ
I once experimented putting in a teaspoon of soda in a 14l bucket and ph shot up to 8+. That is why i got worried. Maybe I exaggerated with the soda.

I would like to raise the kh first before putting any c02 in.
Measure my kh this morning and it's only 2,3 degrees.

Do you have any advice in terms of c02 system?
 
Hi Riccardo1976

I understand what you are saying about the Ph - but If you do not start to add Co2 as you increase your Kh you will see your tank Ph rasie.

I have the same problem - but I have been carrying out some test of my own. I have a large 26 gallon water container - which I use to carry out my water changes.

I have noted that if i add 1.5 tablespoons of soda to the 26gallons the Ph raise to 8.0 and the Kh raises to 8.96.

Peior to carrying out the water change my tank 100gallons had a PH of 7.2 and a Kh of 3.96

Note I am still injecting Co2 into my tank at 50bpm (yes I know it seems a lot of bubbles for such a small increase in co2 - however my reactor was cloged with plant bits ect.. so have now cleared it I expect the ph to drop to 7.0 within the next 24 hours) alway put the reactor on the filter outlet how many times do I need to tell myself this :) I never learn

Once I completed the water change my tank reads

Ph 7.4 and Kh 5.04


it becomes a balancing act to increase Kh while the ph is rasied after each water change but has my test shows the overall ph shift may be small enought so not too stress your fish. The co2 injecting will continue to bring the ph down to your target level. while increasing your Kh to your new target level. hope that makes sense?

regarding co2

I have have a D&D kit and a AM 1000 reactor, AM bubble counter. The D&D kit is great i have had no problems with it - It came with a disposable co2 bottle but i understand I can buy a fitting to allow me to connect the unit to a refillable bottle once i have the funds.

the kit cost me 104 but I have heard you can get the kit for 90 Doh!! the reactor was 45 and counter 12.

at some point I will invest in a Ph controller or Ph computer not sure which one however AM is looking like a good choice. budget 200 controller or 250 ph computer


hope it helps mate

ob1

If you want some pictures i'll post them onto my web site - just confirm what you want to see
 
co2 bottle and regulator
 

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Aquarix 4 nice pce of software here's a chart plotting PH and Kh vs Co2 - cool
 

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Hi All

Apologies for hijacking the thread but thought I should share this all with you.

Myth: A Low KH results in a larger pH swing when adding CO2.

Many people are under the mistaken impression that a low KH results in large pH swings when adding CO2, while raising the KH will result in smaller pH swings. This is not the case. The KH will move the start and end pH values, but the pH swing will be the same for a given level of CO2. You can see this in the chart below, or using a calculation:

Case 1: Assume a KH of 15 degrees, and a starting CO2 level of 4.5ppm, which would result in a pH of 8.0. If we then add CO2, to increase the CO2 level to 28ppm, that would drop the pH down to 7.2, for a pH shift of .8.

Case 2: Assume a KH of just 1.5 degrees, and a starting CO2 level of 4.5ppm, which would result in a pH of 7.0. If we then add CO2, to increase the CO2 level to 28ppm, that would drop the pH down to 6.2, for a pH shift of .8, the exact same as in case 1.

As far as I see it having a low KH just means you will need to add less CO2 in order to achieve your target pH. You might want to get this verified by the forum moderators but this is my opinion.

Hope this helps.

Cheers

Apisto
 

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Youve just made me double check the PH swing theory... and your right. the PH change is in fact the same (all be it from different starting points!)

BUT - if your aiming for a certain CO2 concentration and a certain PH - you will need to alter the KH.
 
Yes that's true enough :nod: , I am just lucky because my KH is already 4 and hence my target range pH can be anywhere between 6.7 and 6.9, and I can see if there is an optimum point for both fish and plants.

What is your KH then ?

Apisto
 
Hi all

Riccardo1976 the kit cost

D&D Co2 kit with 600cc bottle £104
Bubble Counter £12.60
Reactor £45.00

I also abtained a couple of ehiem double taps give to make cleaning a bit easier.


Hi apisto_uk2 and smithrc

I had orginal seen the chart and I too could'nt understand the need to raise the kh from 3.36 to something highter. I agree there seems no piont as one can reach the target co2 level.

ob1
I have read a lot of material; by rising my kH from 3.36 to 8 - I will actual raise my ph to 8, then by adding Co2 19mg/l, I will reduce the ph to 7.1 – I understand why this happens however surly this is the same as me leaving my dH at 3.36 (natural water supply) ph7.6 and adding co2 to 16.6mg/l which will drop the ph to 6.8.. The only reason I can see to increase my dh to above 3.36 is to insure the water ph matches my fish? Eitherway I will need to control the PH shift tightly i.e. PH controller. – I know the higher the kH the more co2 can be added without PH change. Have I missed something about the kH buffering capacity?
I too was unble to see any reason in the co2 matrix (chart) to prove the need for rasing the kh. Until I read pass the co2 matrix and looked a little deeper into kh and what it actual does in the tank.

Our tank water has the ability to counter act and maintain ph i.e. injecting Co2 however there are other factors which need to be taken into account – over time bog wood, fish waste has a additonal effect on Ph – and remember kH is the only thing protecting your waters Ph. Once it becomes ineffective your ph will drop like a bomb!! So by increasing kH you prolong your ability to maintain a steady ph – over a period of time – until your next water change – at which point the kH is again refreshed

There seems to be a lot of people who agree a kh of 4 and below is considered risky when injecting co2, or one has very messy fish and long period between water changes.

I have read in a book called water quality by tankmaster page69 under PH flutuations - is a great starting piont. also a great web site is http://rexgrigg.com/pg1.htm and the best site http://www.drhelm.com/aquarium/chemistry.html


quote taken from http://www.drhelm.com/aquarium/chemistry.html
kH
Carbonate hardness or temporary hardness. Measures the buffering capacity or the ability to absorb and neutralize added acid without major changes to pH. Think of buffering capacity as a big sponge, the higher the buffering, the bigger the sponge. How much buffering does your tank need? The higher the kH (the bigger the sponge), the more resistant to pH changes your water will be. A tank's kH should be high enough to prevent large pH swings over time. If your kH is below roughly 4.5 OdH, you should pay special attention to your tank's pH (e.g., testing periodically) until you get a feel for how stable the pH is.
I hope it helps - I am now on my 11 day looking at kh and my head hurts

cya ob1
 
it's all helping me - i was the one that said you needed to raise your KH (mine is at 8 deg from the tap)

I really want to spend some money on a decent CO2 system... but cant justify it.
So I'm planning my own control system at the moment... :D
 

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