CO2 Help!

[nijat11]

Hello everyone!
My tank is 800 liter + 200 liter sump.
2 weeks ago I have installed CO2.
I have pH controller and 2 magentic valves (one connected to pH controller and another for night control). My KH is 6 and pH is 7.
It is running around 3 weeks. I was droping pH till 6.3 and my drop checker gets lime green, if I will go more it is starting to turn yellowish and fish go to surface.
So now I`m doing small experiment, I set my controller to 6.5 and my drop checker still green (replaced it yesterday). For 3 weeks I have not seen any difference in plants growth.
So my question is, what I`m doing not correct? How should I continue ?
Thank you in advance.

 

[tigertim]

Possibly nothing or you need to up the fertilizer levels , whats your lighting levels ?

 

[GHNelson]

Hi
Just stick to a Green Drop Checker, you are in Danger Of Gassing your fish!
You can grow plants fine with the above coloured checker.
As Tigertim stated, lighting and fertilizers will increase growth.