How to control CO2 in buffered tank
Hi I'm a noob here...wondering if i could get some advice.
I keep wild caught Heckel Discus in a BB tank in RO/Tap mix buffered (non phosphate) at pH 5.8. My parameters out of the tap is pH 7.2, kH 3, GH 6. I am able to adjust kH and GH accordingly using RO water.
I really want to set up a planted tank for my discus, but if the pH rises above 6.4 or so, the discus start to get stressed. Using CO2 injection alone, i find that i am not able to bring the pH down to about 6.0 or so without injeting in fatal amounts. Continuing to use non phosphate buffers seem to be one option for me.
I'm thinking that with the buffer required to bring the pH down to 6 or so, this would render the pH controller (for CO2 injection) useless (if the pH is fixed by the buffer). Is this correct?
The other option is to drop my kH down to about 2 or so. But i'm worried that this might lead to dangerous pH swings (discus are very succeptive to pH changes). Is this a legit worry or am I just paranoid?
The bottom line....how can I hope to bring my pH down to 6.0 and still maintain control over CO2 injection?
Any help would be much appreciated!