Thank you Keithy! There are so many good tanks and systems on here; it would be foolish of me to be anything but humble.
Wolf--you're quite welcome! I'm always happy to help, or offer my advice/opinion. I don't find the need for a pH meter in a planted tank. I suppose that it might be a good safeguard, just like a UV sterilizer is, but I don't believe that you "need" one. pH fluctuations are normal, even drastic pH swings are normal for these fish out in The Wild. I don't think that going from pH 6.8 to pH 6.0 or 6.1 overnight is that big a deal. If you are worried, simply add an airstone and have a pump pushing O2 through the airstone at night after the CO2 goes off. If you're having massive pH swings, something is terribly, terribly wrong with your system. I don't think that most people will ever experience such issues with their tanks, though, under normal conditions with even regular, minimal maintenance.