Originally Posted by Hoppy
And, in my opinion, you had about 40 ppm of CO2 when you did those measurements in the original post.
Not sure what you mean by that Hoppy...assuming you are talking about this post above.
I used to use the API tests but mine were getting old so I switched (don't know exactly why) to Hagen. In reading the booklet (again) last night, if I recall correctly, they also utilize the titration method. I am willing to try anything to figure this thing out (how much CO2). I will try the doubling method. With that said, continued tests give me the same results.
I'm doing some additional experimentation with two tanks: the new planted 20 and a 7 year old fish only (lowly stocked) 46 gallon (no plants, no co2). One of the things I am trying to track is the difference in ph fluctation between night and day. By using the fish only tank as a constant, I hope to understand what I may be subjecting my fish to in the way of fluctuating pH.
Measuring pH at:
morning (new sample at 6:30am)
early evening (new sample at 7pm)
Late evening (new sample at 9pm)
Equilibriated sample (24hrs)
So far, I do see an approx 1.0 point rise in the ph sample after equilization. I do suppose that does tell me that I am getting the right amount of CO2 in the tank. No?
Is a continued change in pH of 0.4 (from day to night) harmful to the fish?