# PH question



## WES53 (Jul 3, 2014)

Hi guys - my PH keeps jumping up and down. What is the best KH number for plants in my tank? Right now my KH is at 2. Thanks!


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## coralbandit (Jul 29, 2012)

If you could get your kH up just alittle(to 3 or 4) you should be fine.Unfortunately it is very diffacult to raise kH (in freshwater) without raising your pH also.
How much does your pH swing and how does it take place(after a couple days,up and down daily like with lighting cycle???)
Have you ever just set water aside for 24 hrs and retested the pH? Often how it comes out of tap is not how it will settle in your tank or even once exposed to air(it will outgas and change).
What is your pH, what does it shift to, and where would you like it to be?


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## WES53 (Jul 3, 2014)

Hi! Thank you for post, i try add CO2 24hrs continue then make me Ph a little better 6,6 to 6,9 and i also turn 1/4 filtration down. i check for few days what happen. THX again.


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## coralbandit (Jul 29, 2012)

Using co2 your pH will return to its original value before you injected co2 everytime you stop the co2.
My 180g goes right back to 7.6 every night and then goes to 6.1 for the entire lighting cycle.This is not the same stress to fish as physically changing the water and natural pH value quickly.Even with proper kH values if you inject co2 you will change(lower) your ph everytime,there is noway to avoid this.
Your plants really don't need the co2 at night as they "respire" without lighting and actually use o2 during this period and produce co2(possibly allowing co2 level to become hazardous to fish).


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## WES53 (Jul 3, 2014)

HI TOM! You are absolutly right about CO2 at night,plant dosen,t need and is wast a gas! but for few days I keep on at night and I have small jump Ph 6,8 to 6,5 (night,day) Yours PH jump out of scale,Do You use Mars Fishcare PH test kit monitoring PH 6,0 to 7,6 ? I test this product with Vinegar and show me 6.1 so means not good! I,m still work on this problem and I let,s you know after few days,also I raise KH to 5 now.


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## WES53 (Jul 3, 2014)

HI TOM! You are absolutly right about CO2 at night,plant dosen,t need and is wast a gas! but for few days I keep on at night and I have small jump Ph 6,8 to 6,5 (night,day) Yours PH jump out of scale,Do You use Mars Fishcare PH test kit monitoring PH 6,0 to 7,6 ? I test this product with Vinegar and show me 6.1 so means not good! I,m still work on this problem and I let,s you know after few days,also I raise KH to 5 now.


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## coralbandit (Jul 29, 2012)

I use a milwaulkee pH controller to turn my co2(solenoid) on and off during my lighting cycle.I turn my co2 on a couple hours before lights and keep it on a couple hours after lights.
I use a standard API test kit to verify my monitor when it is in scale.
I have also spent alot of time adjusting my controller and didn't always add so much co2 to lower my pH so much.
For simplicity I also have a drop checker in my tank so I can always give it a quick look.


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## Jep (Jul 15, 2014)

trying to get the Kh to 5, and the pH to 6.8


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