Arnim wrote:

Hi all. Still researching my deal but my online auction CO2 system arrived
today. My concern now is the pH swings. My tap water pH is pretty high,
about 8.0+ up to 8.4. All my tanks have been pretty stable at 8.0 for the
past couple of years and the fish have adjusted fine. If I just put the
solenoid on the timer with the lights, will the CO2 swings be too great as
the pH tends to equilibrium of 8.0 overnight? Luckily my KH is pretty high
so I think I can dissolve enough CO2 in the water but will have to pump
enough CO2 to get the pH down to at least 7.4 or so to get the 15 ppm.

Tom Barr has pointed out that natural lakes can swing two full pH points from
day to night without harming the fish. If you are concerned, run the CO2 24
hours per day. It will tend to swing a bit up during the day, a bit down at
night, probably just 0.2 or so. I did detailed testing in my tank a year ago and
found that the swing was less than 0.2.

A controller adds cost, labor (setup, callibration) and risk to the system.


I'd
rather not have to start cutting the tap water with RO water if I don't have
to.

What are you thinking here? That will lower your pH even further.


Turn on the CO2. Watch the plants grow. Relax.