55 Gallon Tropical Tank Suggestions

[Essjay]

That type of softener is fine to use

 

[Essjay]

Hmmmm, I've just googled electric water softeners and there appears to be 2 types.
Some still use salt to swap the hardness minerals for sodium.
Others are more properly called descalers, and they stop calcium attaching to things but still leave it in the water.

Before using the softened water, can I suggest you test it for GH - or take some to a fish store and ask them to test GH. If it's the descaler type, the water will actually still be hard, it just won't create limescale deposits.