The Ph drop is far from bogus. This is not about perfect science. Nothing with home aquaria is perfect science. It's about what is going to help in most situations and the ph drop does indicate whether you have adequate co2 is most situations.
I have tried to understand this "1 pH drop" method and wanted it to succeed as we have nothing much to go by in this hobby. Everyone was invited to participate in my thread, I have to mention, you have not.
What I have demonstrated, with references, was that 1.0 pH and 1.4 pH drop may indicate anything between 20 and 100 ppm CO2, depending just on location.
CO2 levels between 1.0 and 1.4 pH drop per location,
20 – 50 ppm CO2 rural
30 – 75 ppm CO2 town
40 – 100 ppm CO2 city
No one is demanding perfect science here, but isn’t this too much inconsistency? If you still want to know more why I call this method bogus, look at Diana Walstad reference:
“I picked 0.5 ppm CO2, a value frequently quoted by scientists, based on Wetzel's textbook*:
"The amount of CO2 dissolved in water from atmospheric concentrations is about 1.1 mg/l at 0 degrees C, 0.6 mg/l at 15 degrees C; and 0.4 mg/l at 30 degrees C." “
If we go by this scientific reference, then 1 pH drop represents 5 ppm CO2 in our aquariums. How is this "1 pH drop" not bogus method?
References
pH Drop CO2 accuracy thread
*Wetzel RG. 1983. Limnology (Second Ed.). Saunders College Publishing (Philadelphia, PA), p. 202.