Myself and Amano seem to have parallel paths here, we both turn CO2 off every night in every tank we do. I asked him why years ago, he just said "it was Taboo in Japan". Not much of an answer. We both think this independently and came to this method long before we met or knew of eachother.

1#
I have my reasons for not doing it at night: common sense says, it's just not needed.
Waste.

2#. Error, I can get away with adding more during the day when it's most needed without overdosing the fish and O2 is only produced during the day(never at night).
this allows more CO2 and more O2 and less CO2 and less O2 concentrations to coincide..........not high CO2 and low O2.
That's bad/worse for fish than any nutrient other than a few trace metals and NH4 etc.

I find it odd some will howl over 30ppm NO3 being too high, toxic, bad for fish etc etc etc.......yet feel no issue adding 30ppm of CO2.

CO2 has killed far more and is far more toxic than NO3, PO4, or K+ to fish.
But they do not give it a second thought, there is no Fear mongering going on with CO2..............

I've never quite understood this.
The logic is missing me here.

CO2 can change rapidly and go from 2ppm to 30ppm inside 1 hour, and it can cause algae and other secondary issues. Given that, unlike NO3/PO4/K etc all which do not change much over the same time frames...........CO2 is obviously much more critical.

Also current is a huge issue, do not reduce current to save/conserve CO2, you will reduce the O2 which is much more critical to fish health.
With good current, you also have better CO2/O2 exchange with the plants.
We can always add a bit more CO2 during the day to make up for any losses.
It's cheap and we are not adding it at night.


Regards,
Tom Barr