Re: [RML] Melanotaenia trifasciata and pH

Bruce Hansen (bruceh at
Sun, 15 Aug 1999 20:29:15 +1000

As far as pH is concerned, I remember talking to Ed Fraser (at Pisces
Enterprises) who keeps some fish in his plant tanks. At one stage he tried
continuous monitoring of pH in some of his tanks, and gave up after a couple
of weeks as the swings in pH associated with photosynthesis were so extreme
and seemed unrelated to any distress in his fish that he deemed it
unimportant .

Perhaps it is not the pH but the chemical nature of the individual acids
that si important.


Bruce Hansen, A.N.G.F.A., Advancing Australian Aquatics.

Bruce Hansen, ANGFA, caring for our aquatic ecosystems.

Please visit us at

----- Original Message -----
From: Adrian Tappin <atappin at>
To: <rainbowfish at>
Sent: Sunday, 15 August 1999 13:13
Subject: Re: [RML] Melanotaenia trifasciata
> My weekly monitoring definitely showed that there are _wild swings_ when
> comes to aquarium water. Even between morning and night time.


> In well-buffered aquariums with alkalinity levels above 50 ppm (mg/L), the
> pH will be more stable. In the morning, carbon dioxide levels are high and
> pH is low because of respiration during the night (carbon dioxide forms a
> mild acid when dissolved in water). When a suitable light source is
> provided, algae and other aquatic plants will produce carbohydrates and
> oxygen from carbon dioxide and water by photosynthesis. As carbon dioxide
> removed from the water, its pH increases. In aquarium systems, the pH will
> generally drop in relation to the fish load, biological filtration,
> and maintenance schedules. Therefore, the pH in an aquarium system is
> biologically different from that found in nature.