Yup as Atxpunx mentioned, the timer is for the solenoid valve. Basically the plants can only use co2
during photosynthesis when the lights are on. You set it to shut your co2
off at night when the plants produce o2
I'm new to co2
as well and will investing in a pressurized system soon. I'm using DIY right now.
Oh and for the drop checker that indicates the amount of pH and co2
you have going on, not sure if you already know this, I've learned that you shouldn't mix your tank water with the indicator solution. The instructions that came with my DC
said to use tank water but that's outdated and using 4 dKH
reference solution will give you a more accurate reading.
You can either mix your own 4 dKH
(with distilled water and sodium bicarbonate) which I find it hard to do (or I'm just lazy rather), or you can buy it already made on ebay (which I did).
Here's a link I found if you want to make your own:
And the ebay seller I bought the 4 dKH