[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [APD] KH goes UP after adding CO2



Hi Liz, thanks for the reply.

My pH went down from around 8.0 to 7.2, but by then the smaller fish 
were at the surface.

I backed it off and just tested again a minute ago and the pH is 7.6.

It's hard to know what pH to shoot for when the KH is going up on me.

7.2 pH is perfect for a KH of 23 or so (43ppm CO2) but when that KH 
moves up on me like that 7.2 indicates a CO2 concentration that can be 
deadly.  (55 ppm CO2 at 29 dKH).

I am surprised to learn that kH goes up with CO2 addition, I have been 
studying this planted tank thing for a number of months in preparation 
for my first try and had not read anything about this.

Liz Wilhite wrote:
> On 2/4/06, Barry Anderberg <apd at swoobs_org> wrote:
>   
>> I can't figure out what it could be that is causing KH to go up..
>>     
>
>
> CO2.  CO2 when added to water produces carbonate and bicarbonate.  What did
> your pH do when you added the CO2?
>
> CO2 and water form a complex solution with species that occur at different
> ratios at different pH.  If you have a solution that is saturated with
> carbonate and you add an acid to it you can see it fizz as CO2 is produced.
> This is the same kind of reaction that occurs when you pour an acid on
> limestone.
>
> Liz
> _______________________________________________
> Aquatic-Plants mailing list
> Aquatic-Plants at actwin_com
> http://www.actwin.com/mailman/listinfo/aquatic-plants
>
>
>   

_______________________________________________
Aquatic-Plants mailing list
Aquatic-Plants at actwin_com
http://www.actwin.com/mailman/listinfo/aquatic-plants