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

Re: Ph Drifting Down Between Water Changes...

Hi Dave,

Thanks for taking time to answer. I added a little NaHCO3 this morning and
I am already seeing a gradual ph rise and more pearling. I ordered some
potassium bicarbonate from The Science Alliance web site. I will be using
this in the future so as to not add sodium. Do you have any BIG PRINT
directions for mixing this stuff?... I bailed out of chemistry in college
when I hit quantitative analysis :-) 

Also, my Gh is ~8 should I really be aiming to get my Kh up there or would
4-6 be OK?

Thanks a lot,


>Date: Mon, 19 Feb 2001 08:43:36 +0930
>From: Dave & Robyn Wilson <rwilson at octa4_net.au>
>Subject: Re:  Ph Drifting Down Between Water Changes...
>>Over the last month or so I have found my average PH to be slowly drifting
>>down. It used to be around 6.9 now it is 6.65. Here are some details.
>>Tap- ph 8.2, kh 4, gh 8
>>Tank- ph 6.65, kh 2, gh 8 (before lights this AM)(changed water yesterday )
>Your tank is using alkalinity, buffering capacity or carbonate 
>hardness (KH) at a rate you can calculate.   Try adding some 
>potassium bicarbonate to raise your KH up closer to or level with 
>your hardness (GH).   To raise the KH 10ppm or about half a German 
>degree, which I think is the measurement you have used, add 20 grams 
>per  cubic meter (1000 litres).   You can use sodium bicarbonate as a 
>buffer but plants don't use the sodium.   Potassium bicarbonate will 
>provide a potassium source for the plants as well as buffering 
>capacity.   Potassium bicarbonate is a bit harder to find than the 
>other but worth the extra effort.   Potassium bicarb is also about 10 
>times more expensive than sodium bicarb but you don't have to use 
>much.   When you add the buffer the pH will rise so you may increase 
>the CO2 rate if it is not on auto.   Plants are about 44% carbon dry 
>weight once you raise the KH they can get more carbon and will 
>probably start bubbling again.

           Paul Mouritsen.....mourip @ erols.com