My tank is a freshwater 29-gallon with a closed top, a light that stays on for approximately 8 hours a day, two underwater plants, a small cluster of red root floater plants, five harlequin rasboras, and a plecostomus that's only a few inches long.
Just did a water parameter test: all parameters are perfect (even pH) except for alkalinity, which is showing up pretty low. What can I do to adjust the alkalinity and bring it up a bit? (The only advice I'm finding online always correlates an alkalinity problem with pH, but the pH in my tank is perfectly fine!)
Additional note: the tank has been up and running for two years.