Is water softener water ok for my plants? The GH in my tap water after it’s been softened is obviously 0, but I read somewhere that it might contain some sodium which can be detrimental to my plants. Is that right?

I do remineralize the water with Seachem Equilibrium back up to a GH of 6.

Water softeners replace each Ca and Mg ion with two Na ions, so your softened water has a considerably higher TDS. Plus, you are adding Ca and Mg back into your water with Seachem Equilibrium, which raises the TDS even higher. Your softened water could easily be too salty for many aquarium plants.

The general consensus is to not use softened water for planted tanks.

It's not the end of the world if you have to use GH boosted softened tapwater. Is it ideal? no, but is it fine to use? Yes:

90 gallon, 15dKH, 6dGH, 500+ ppm TDS, fish / neo shrimp thriving and breeding:


20 gallon, 15dKH, 1-2dGH, 500+ ppm TDS, fish / neo shrimp thriving and breeding:

Buy a TDS meter. They are pretty cheap off of amazon (lots of good ones under 15 dollars shipped) and pretty useful. Measure your tds and you will know the answer. Have a tds over 1000? Might have some issues.

+1.

I have softened well water and got along just fine for a long time with it.

Switched to RO and things got even better. But it's a matter of degree.