Hi All,
I have a heavily planted 10 gallon tank that's been running for 6 months (4-glofish tetras, 6-guppies, 2-otocinclus, 1-snail). Fish and plants are all doing well. Nitrates are usually close to 0. I add liquid food as needed to bring it up a bit. My tap water has 0 kh, 0 gh, and low pH (usually around 6). I've been adding seachem equilibrium to keep the snail happy, this has been working to keep the gh up. I was adding baking soda to bring up the kh and keep the pH around 7. The last time i was at my LFS I got some "API ph up" figuring that maybe it was safer / better than baking soda. When I add it to the tap water and test I see the expected increase in kh and pH. However when I add this water to the tank it seems to have the opposite effect on the pH. Testing the water after adding the new water shows very low pH (off the chart), and 0 kh. It is lower than both the existing tank water and the new water. I did several water changes to try to raise the pH with "ph up" before switching back to baking soda. Does this make sense to anyone? My chemistry is very rusty.