Turns out, that fish gasping incident was a false alarm. I'm down to 5.5 ph and the fish/shrimp seem fine, HC is pearling as are a couple of stems and no more algae growth whatsoever.
It's interesting trying to understand how ph works. If I didn't have a controller, I wouldn't have thought twice about turning the CO2 up and up, but since the ph reads so low it makes me nervous.
I have read over and over the the ph swings associated with CO2 levels don't bother the fish, and that the gassing effect isn't related to the ph at all, it's because the fist can't respire due to lack of O2 in the water or there being too much CO2. So, does that mean that this low ph reading that I get on my controller isn't really risking the fish at all? In other words, so long as the CO2 and O2 levels are good, I shouldn't care about what the ph controller reads?
Very interesting, and exciting because I am really seeing some progress. Plants are starting to look very healthy, and algae seems to have just stopped growing! The HC on driftwood is amazing - if only I could take a decent photo of the tank
Sean, I've been too lazy to break out the test kit but I will tonight!