If my memory serves me right, I think Mike is just starting out on his CO2 adventure
I have found that this is quite normal and nothing to worry about. If you have a lot of surface agitation it could possibly go back to blue overnight, but mine is light green in the mornings after no CO2 at night, but then I am running it at virtually yellow during the photoperiod
I have my CO2 on 2 hours before lights on and turn it off 2 hours before lights out. In your case that would be CO2 on at midday and off at 8pm and leave lighting set for on at 2pm and off at 10pm. It appears that doing this gives the plants maximum available CO2 at lights on (apparently the most critical phase for plants), and for the last 2 hours when your gas is off, the plants are on cruise control and just use up the CO2 that's left in the water column before lights out.
Seems to work for me. The biggest thing I noticed was that the pearling increased dramatically when I change to these timings.
yes stop the CO2 otherwise it is a waste. I try to perform my water changes before CO2 is on, that way, there is none wasted, and it will be like every other day.
It would still probably drop back to blue over night, mine does. 12hrs+ is usually plenty for it to gas off.
I believe that a tank with a lid does retain CO2 overnight, somewhat better than a tank without.
Like Aaron, I too try to get my water changes done before CO2 comes on. Maybe I'm just paranoid about keeping my CO2 levels the same each day at lights on, after the mission I had with BBA when I wasn't injecting enough .
I've managed to reduce my time for water changes to 1/2 an hour for water out and water in. However, the trimming and tidying,........... now that's another matter altogether .
Don't be alarmed, my drop checker goes from blue to green before my CO2 comes on after water change .
Just bear in mind that you did a 50% water change, so the 50% that was left in the tank still has the residual CO2 left over from the night before, which is what your DC is telling you.
This is nothing to worry about .
Also I assume that my plants are using the co2 injected as otherwise the dc would turn yellow if they were not?
I think you answered your own question there Mike , providing you're not losing too much with any surface agitation.
My tank took about 2 weeks to adapt to it's new CO2 and EI dosing regime, after that the growth rates went nuts .