Hi,

The tap water at my work place has a pH of 7.8. So far when I've done water
changes in my planted tank at work, I've been lowering the pH (to ~6.8)
using a commercial kit which uses sodium biphosphate. Recently I've noticed
that my phosphate level is 2ppm. Is there another way to lower pH of the
clean water without resorting to installing an RO system etc.

Thank you in advance.

Kevin