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Re: PH Questions
Your tap water has dissolved CO2 that causes your pH to read lower than it
does when it reaches the atmospheric equilibrium. From the CO2 charts, your
tap water has in excess of 30 ppm of dissolved CO2. To test this, draw a
sample and either aerate it, vigorously shake it or just allow it to sit
uncovered overnight. It will now measure at your 7.6+ pH. Now get a straw
and blow into this water and immediately retest. Your pH will drop.
The reason you have been unsuccessful in lowering your pH is the high
buffering capacity (KH) of your water. Before your pH will change this
buffering capacity must be overcome. Your current pH of 7.4 and a KH of 13
is providing you a good CO2 concentration (@ 15 ppm). If you got your pH
down to 7.0 as a result of increasing the CO2 content, the fish would not
enjoy these high CO2 levels.
There is nothing wrong with having a pH of 7.4. I would be satisfied with it
as is and not feel any urgency to modify a thing. Not everyone maintains a
neutral pH and there is no reason to think you have to.
> Date: Sat, 14 Apr 2001 03:40:46 -0500
> From: "C. Bostick" <chrisbos at bayou_com>
> Subject: PH Questions
> My tap water is 7.0 or slightly acidic, with a kh of 13, but the water in
> two aquariums is 7.6 or higher. I don't have any of the ph altering rocks
> or anything like that. I first tried the ph down product with no luck,
> Seachem's neutral regulator with no luck. I have totally gave up on it,
> what can possible cause this to happen? There is nothing in the two tanks
> the same as far as decorations or rocks go. The only time ph has dropped
> below 7.6 was with the addition of a co2 bottle, ph is now at 7.4 , but I
> want a neutral ph like everybody else. Given the fairly hard tap water,
> which I understand would make it have a strongly buffered ph, why does it
> suddenly jump so high when the water is poured in the aquarium and so hard
> to bring back down?
> Chris Bostick