Dialling in CO2 on a dark start tank

[Ruskie]

Hi all,

Disclaimer - I’m new to CO2, this is my first time setting it up.

This maybe a mute question but I couldn’t find any info regarding it.
I'm currently doing a dark start on a tank and thought this would be the best time to try and dial in the CO2.
I set it up over the weekend and put the CO2 on a timer that works around what my lighting schedule will be once the dark start is complete and I eventually turn the lights on - 2 hours before on and off an hour before lights out. Currently on about 2 1/2 bubbles ish per second, 100L tank.
Day 1 the drop checker still looked too blue at lights on time but was green/lime green a few hours in and at lights out so I figured it needs tweaking a little.
Day 2 the drop checker was blue/green before the CO2 started and was bordering yellow at lights out. The only thing I tweaked was turning up the pressure slightly from 30 to 40 psi.

As there are no plants in the tank to take the CO2 I’m putting in I guess there’s still going to be a surplus from the day before? Could this be why the DC was slightly green before starting on the 2nd day or should all the CO2 be gassed off overnight?

I guess my question is, is there anything I need to be doing slightly different being as I don’t have any plant mass at the minute? Or should I just be aiming for a green DC for lights on?

Thanks

 

[John q]

For now just aim to get the dc green by the time the lights potentially go on and remain green until an hour before they go off. Just be aware the settings will likely need tweaking after the plants get added.

Once you add plants to the tank the whole dynamics are going to change, the gas will get consumed during lights on and then the plants will add co2 during the night, flow around the tank will also change and that will have a big impact on how effectively the gas gets dissolved in your tank.

 

[Ruskie]

Thanks @John q

Appreciate it will still need tweaking once plants are added but if I can get the bulk of the fiddling out of the way before that hopefully that will get me off to a good starting point!

As I’m in no rush I’m thinking about running the CO2 a day on and a day off at the minute while I tweak it. I feel that way I can get a better reading from the DC at ‘lights on’ without any potential false readings from surplus CO2 from the day before that may or may not be present from not having any plants.
Unless I’m completely over thinking this!

 

[John q]

Unless I’m completely over thinking this!

Lol nothing wrong with over thinking.

I'd personally do it on daily basis, you'll get a more realistic result.
You're always going to have some residual co2 in the water column in the morning, be it from leftover remnants of the gas not fully off gassing or from the plants excreting co2 during the night period. Starting from equilibrium levels (1~2 ppm) of co2 every other day wouldn't be something we encounter in the real world of gas injected tanks.