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Re: Ph Drifting Down Between Water Changes...
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