pH stability for Taiwan bees
I have a newly set up tank that is done cycling. GH5, KH 0, TDS 120. There are only some plants inside. The pH meter says that the pH goes to 6.8 during lights on, and 6.1 during lights off. I don't add CO2, so this must be the plants photosynthesizing. Using UNS control soil, which doesn't seem to be buffering much. However, I also used the API liquid test kit, and it said 6.5 each time. Well, assuming the probe is right, is this too much of a daily pH swing?