Hey Tetra77 Welcome to our Forum!
I am assuming the tank has been up for a while and is fully cycled.
While E46er is giving you good advice on not chasing your tail with pH altering chemicals 6.0 is a little low and I can understand your concern.
It would help if you could post your GH and KH.
The baking soda will raise the buffering capacity of the water (KH) and act raise the pH a bit but IMO I think you need to look at both GH and KH acting together.
Post the numbers and we can go from there
Regards,
Jay