HALP PLZ! I have a 55 gallon planted with a low stock of other fish, 6 kuhli loaches, and 5 RCS. I have two pieces of DW/no rocks. Parameters were 0 nitrites, 0 nitrates, 0 ammonia, ph 7.6 consistently, kh 6, gh 4.5. Do a 25% water change once a week and lights on for 3 hours in the morning with a 4 hour break and 3 hours in the afternoon. Plant growth was slow but steady. Dose with thrive 2-3 times weekly and have some brown algae but that's going away. No CO2. Water has also been consistently yellow (assuming tanins) and have a sponge filter and canister filter.
At the beginning of this week my ph jumped up to between 8.0 almost 8.2 and has stayed there all week. My plants are not thriving as much and I cut back my lighting strength from max to try and help. My other 2 planted tanks aren't having this issue. I still dose with thrive but now I'm feeling I should stop? And I know keeping it stable is more important but I just don't understand the change in ph... can someone explain? I'm worried it's going to continue to increase.