High PH

[Peng Kang Hill]

Hi all,

My KH has been constant at 4.5 with a PH of 7.5. I have difficulty reducing the PH - my aim is to reach below 7.

CO2 is at 3 bubbles /sec and water from the tap is with KH 1.

What can be the problem?

Peng Kang Hill

[oqs]

What method are you using to dissolve your CO2? Reactor, diffusor or ?? That might be the problem.
Another one i can think of is the size of your tank. How big is it? 3 bubbles per second in a 2ft tank and a 12ft tank makes a lot of difference.

I'm really curious how did you measure your KH so accurately (to .5 accuracy)? I think most test kits do the test by drops of the reagent, unless you are using specialised equipment or you can split a drop into half? [] What are you using to measure your pH?

[sherchoo]

Just to add on:
You could also examine if there's anything that is dispersing your CO2 from the water. Water agitation tend to give a higher rate to equilibrate the co2. Less CO2 would result in higher pH value.

[tcy81]

maybe u wanto add peat into yr filter

[geoffrey]

Adding peat will confuse your CO2/KH/pH relationship. In a planted tank, we usually lower pH with CO2.

[Peng Kang Hill]

Thanks all,


I'll try to answer the questions one at a time:

Mine is a 3ft tank, using a ceramic diffuser. CO2 running at 3 bubbles/sec. Water agitation is minimal.

How I get the 0.5 accuracy is I double quantity of the water tested and thus able to reach that conclusion. Tested on a tetra test kit.

Having said that, is PH 7.5 fine with plants?

.. Peng Kang

[Sleepy_lancs]

Well, I agree with Geoffrey. No additional stuff except with CO2 to reduce the PH level. I don't know about others but I also used to have this trouble so I change my reactor to an external (because internal seems to have too little space for that much bubbles) and just keep increasing the bubble count until my PH is about 6.8 and thats it. An yes, check your return pipe. Make sure its at least 2 inches below the water surface and pointing downwards. I increase it slowly (by the day). By the way, algae drives up PH as well.

[juggler]

Is your high pH of 7.5 due to coral chips in your substrate or filter?

[vinz]

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On 11/21/2003 12:49:58 PM

Well, I agree with Geoffrey. No additional stuff except with CO2 to reduce the PH level. I don't know about others but I also used to have this trouble so I change my reactor to an external (because internal seems to have too little space for that much bubbles) and just keep increasing the bubble count until my PH is about 6.8 and thats it. An yes, check your return pipe. Make sure its at least 2 inches below the water surface and pointing downwards. I increase it slowly (by the day). By the way, algae drives up PH as well.
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Algae drives up pH? Can you elaborate?

[Peng Kang Hill]

Hi,

As far as substrate is concerned, no coral chips. Not in filter either. But I do have 3 very beautiful oyster shells and a rock that may possibly be limestone. But they've been there ages already, even before the plants.

Do I need to remove the oyster shells?

Peng Kang

[hmph]

yes...please remove them all. :P

[sherchoo]

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On 11/26/2003 9:58:59 AM

yes...please remove them all. :P
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You don't have to remove the shells if you don't want to. Your kH indicates that it's not the main problem.
Like mentioned earlier, examine your CO2. Use it to reduce the pH value.

[jellydot72]

Hi P K,

pardon me asking a stupid question[] You very sure the gas in your cylinder is CO2, arr... food grade? This is the only thing I have in mind after all info u shared. Or....your CO2 indicator, faulty?

jellyman

[murphys33]

if the surface does not break, will there be any loss of co2 though the rainbar? just wondering about this for a long time..can someone care to explain? thanks

[jellydot72]

I suppose as long as there is minimum or no drop of water as in water fall effect there will be minimum lost of CO2. I see it this way....if you were to stir a glass of coke, you soon find that the CO2 in it escape at a faster rate.

And normally these water drops area have lots of aglae!!! Like those in reservior where high water aggitation is observed, more oxygen there?

[E33]

Your case it is more likely caused by the sea shell and other stuff etc.
Why not try removing it?
Another question, what kind of gravel you are using?

[jellydot72]

another sign if it is the shells will be calcium layer on the glass at the water edge when they react with CO2!

When I first started planting in 1996, Most LFS dunno what to advise and hobbyist like me at that time also gong gong, put in sand that contain coral chips then some more pump in CO2 from those Tetra brand green color inverted cylinder type from an aerosol (this type was what that is available commonly in those time). Result...heh heh heh...high PH lor.... then tried adding PH down liquid (again LFS idea at that time )

jellyman

[Lme]

can i check with you guys, after reading all, am i right to say that we should not use PH down chemicals to reduce the ph?

Thank you

[geoffrey]

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On 11/28/2003 9:25:27 AM

can i check with you guys, after reading all, am i right to say that we should not use PH down chemicals to reduce the ph?

Thank you
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Only for planted tanks.

[Peng Kang Hill]

Thanks guys.

But what does calcium layer on the glass look like?

Peng Kang