Ph KH C02

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

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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

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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

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