Ok, so I am pretty new to CO2 in general. This is my second tank with CO2, but the first tank was more of a fly-by-the-seat-of-my-pants just use a drop-checker approach.
Thanks to fellow crunchers here, and endless reading on the 2hr Aquarist, I think I am a teensy bit smarter now, but still wading through relatively uncharted waters for me.
Tank is about 10-11 days post planting. Some algae on older leaves that will be annihilated during tomorrowās large water change, but I think I have things close to a coasting level. The one rather critical data point I am missing right now is
ppm CO2. I am still waiting on the replacement base reagent for the LaMotte CO2 kit (I can't even tell that they actually shipped it), but my Hanna kit is out for delivery today, so I am hoping to test it later today and tomorrow.
In the meantime, I have been rearranging things in the cabinet for the umpteenth time, and at least gathering data on
pH fluctuation throughout the photoperiod, and working to get that as stable as possible. As this is a majority slow-growing plants tank, with a few higher demand species, I am restraining the photoperiod to 6 hours total at the moment, including a 15 minutes ramp up/down.
My biggest surprise was my actual degassed pH level at 7.3. Apparently I wasnāt shaking my water sample hard enough or long enough before I sprung for the
magnetic stirrer. Prior to that I was concerned about just how low my pH may have to go to accommodate a 1.2-1.5 pH drop, so definitely a few dollars well spent.
Then it came down to timing. The Apera has helped me immensely on that front. I started out injecting CO2 5 hours prior to the start of the photoperiod, but that seemed a smidge early. I have now shaved that down to 4, so that saves a few bubbles of gas. I am also turning CO2 off 2 hours prior to the end of the photo-period without too drastic a shift in pH at the end of the photoperiod (too early?). CO2 off to lights off is about 0.1-0.15 change in pH. Overall, I think I am in a good place (ppmās pending of course) at least in regards to the shape of the curve. If I read Roccoās
dialing in CO2 docs correctly, I should be aiming to have CO2 equilibrium throughout the entire photoperiod, but not injecting too fast, or too late.
Photoperiod is 2:30P to 8:30P right now, with CO2 on at 10:30A, off at 6:30. Degassed (7.3) to equilibrium (5.8) has been consistent each day for the last several days, and the pH of the tank is consistently returning to 6.5 prior to injection resuming the following morning. So right now it's a 1.5 pH drop from degassed to equilibrium.
Only minor issue has been the flow meter not always coming back up to the right level, and drifting downward a little when CO2 first starts up, so still tweaking that a little. Otherwise, things seem stable, just need to see if it's enough with the CO2 titration once the new kit arrives. Think I might still be a little under based on the drop checker at the moment. We'll see...
My schedule isn't quite so ridiculous today, so I will check it again tonight before the CO2 switches off. Brighter light does make it easier, but I am probably still reading it a little high.70 seemed crazy high though, for not even a full pH drop, which is why I didn't believe that value.
I've had the kit for 20 years, but I got refill reagents for Christmas. My base reagent expired Feb 2026 and at this point, it's a bit too late to complain. However, its sodium hydroxide. I think it will be OK. I recently had to re-set my CO2 and my Erio quinguangulare has started back growing again, so my CO2 must be OK. Its notoriously picky. Yeah, if I had just bought it, I'd be contacting customer support, but as it is, I'll make do. Glad you posted your reply to Jackson.
. It frequently resets permissions, and then can't find the Bluetooth controller. Also, I have burned out two of the 12V AC/DC power supplies in the last week! (This is my second screen, because the first one arrived damaged. Kudos to ARC, though, for replacing it as it is quite pricey and expensive to ship for a tank this size). The power supply for the replacement screen started to fail on Wednesday, and caused the entire screen to start flickering. Rather than place a 'seizure warning' label on the tank I swapped it out for the power supply from the original screen. I had sent the screen to the dump, but kept the power supply 'just in case'.
this morning, too! I have a new 12V/5A power supply arriving from Amazon today. If I burn through that one as well I will just break out the multimeter and see if I can figure out what's going on. Not that LEDs draw a ton of power, but I am wondering if the screen is too much for the supplied cheap power supply. Who knows?
