Hi mate,
Yes, it means a lot to me. I can see that from 2pm to 3:45pm the pH did not fall, which means that gas was being injected for almost 2 hours(?) without any effect. Having said that, we should have gotten a measurement just at lights on because it is possible that the plants were consuming enough CO2 to raise the pH back to 7 from some lower value. In either case this is very poor efficiency, so either you have a CO2 leak somewhere, or the injection rate is too low, or both of these.
It's not clear to me from your description what time gas is turned on/off or when lights are turned off.
You may need to play with increased injection rate and turn-on/shutoff timing. I forgot to ask what the tank water's alkalinity is. If it's below 8 or so (as measured by your KH kit) then you might want to target a lower minimum pH instead of 6.5, and ideally that would occur at about 4PM (but that is a really tall order and you would require sorcery to achieve that without annihilating the critters later in the day). Obviously, you have to be careful to not gas the fish, but definitely have a play.
Alternatively, if you fear for the safety of the fish, you can leave the injection rate alone and supplement with liquid carbon, but that cost more money, and some of your plants may not appreciate it depending on the species.
Cheers,
Yes, it means a lot to me. I can see that from 2pm to 3:45pm the pH did not fall, which means that gas was being injected for almost 2 hours(?) without any effect. Having said that, we should have gotten a measurement just at lights on because it is possible that the plants were consuming enough CO2 to raise the pH back to 7 from some lower value. In either case this is very poor efficiency, so either you have a CO2 leak somewhere, or the injection rate is too low, or both of these.
It's not clear to me from your description what time gas is turned on/off or when lights are turned off.
You may need to play with increased injection rate and turn-on/shutoff timing. I forgot to ask what the tank water's alkalinity is. If it's below 8 or so (as measured by your KH kit) then you might want to target a lower minimum pH instead of 6.5, and ideally that would occur at about 4PM (but that is a really tall order and you would require sorcery to achieve that without annihilating the critters later in the day). Obviously, you have to be careful to not gas the fish, but definitely have a play.
Alternatively, if you fear for the safety of the fish, you can leave the injection rate alone and supplement with liquid carbon, but that cost more money, and some of your plants may not appreciate it depending on the species.
Cheers,