Confused about high PH

L

littlecowgirl

Registered Member
Mar 16, 2007
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Hi
I am confused about why my Ph seems to go high 8.2 at the moment. It does not stay constant. (7.8 - 8.2) My GH is 80 ppm and my KH is 50 ppm.

Here is where I get confused. I get my water at a friends place, she has a 30g tank and her Ph is approx. 7.6. sometimes after a water change it's at 7.4 and she adds a little baking soda and then all is fine. I have a 30g tank I get my water from the same source and mine is at 8.2 the day after a water change.

I have one planting rock and two plastic pieces that I got at the LFS, we both have live plants. Why might my Ph be some much higher.

Thank you for your help.
Laurel
 
What kind of gravel are you using? Aragonite, crushed coral, stuff used for cichlids and saltwater will buffer your pH.

test kit possibly wrong?

In either case, don't worry about the pH. It won't harm your fishes if you have a high pH.
 
I don't think high PH really affects fish, unless you're breeding them. My water's constantly around 8.5, even after I test it straight out of the source. Do you have a water softener? I think the salt from the water softener would raise the PH...which is probably the reason in my case.
 
The type of gravel is Deco Rock, it says on the bag it will not effect Ph.

My friend does not have any drift wood in her tank.

The test kit was new but my be wrong? I have tested our water which I know is hard and it came out hard on the kit. The water is not going through a water softner, it comes straight from a well.

Thanks again for the help.
 
it sounds like a carbon dioxide issue to me. many municipal water and well systems contain alot of carbon dioxide. carbon dioxide is only water-soluble, when pressure is maintained .. as in the pipes which transfer water through your house. this CO2 is in equillibrium with carbonic acid ... which will lower your pH. when the water is discharged from the pipes, the pressure is released and the solubility of CO2 diminishes. the CO2 degasses to the atmosphere and the result is a higher pH as the system equillibrates to a 'normal' pH. you get your water from your friends house ... by the time you get it into your tanks, perhaps the CO2 has been discharged and your ph goes up.

why? Carbon dioxide dissolves slightly in water to form a weak acid called carbonic acid, H2CO3, according to the following reaction: CO2 + H2O --> H2CO3. After that, carbonic acid reacts slightly and reversibly in water to form a hydronium cation, H3O+, and the bicarbonate ion, HCO3-, according to the following reaction: H2CO3 + H2O --> HCO3- + H3O+

the carbonate discussed above (measured as kH) acts as a 'buffer' which reacts with any 'acids' in your water to neutralize them. when you add chemicals, you're really adding acidic buffers (usually phosphate ... these cause major algae blooms) which cannot work to effectively lower your ph since they are 'used up' by the carbonate.

a way to test this is to draw water from your friends house, take the pH, and let it stand for 24-48 hours. take the ph again after that period of standing. does it go up to match the ph in your tank?
 
do it again, and this time put an airline in the water to keep it stirred up. wait 48 hours. are you certain there's no lime rocks, gravel or decorations in your tank?
 
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