Fish and water hardness

Not too much, most folks have excellent results hoiwever, if they properly acclimate hard to soft water.

AF cichlids are a classic case. Rainbows etc?
They do great. Some Tangy's need special care.

Acclimate very slowly over time and they generally do well.
Also, you can add GH, this is what most of the hardness salts are comprised of in many places, not so much bicarbonate(KH).

Add GH booster(Grumpy has some right there in the your local town. See Rex Grigg)

Regards,
Tom Barr

 

You can use the SeaChem EQ chart, it's relatively close to what the Gh booster will do.

The GH booster will add a bit more than the SeaChem will.

But GH is a rough guide anyway.............not some critically measured micro nutrients, same with K+, few folks fret over that as long as they have non limiting levels.

The other way is to simply add some to the tank and measure the volume, wait, 4-8 hours, then measure.

Or you can add a 5 gal bucket of water and add enough to get 3 GH, make sure to mix and have a powerhead in there to keep it mixed and well circulated.
It'll be a fair amount if the GH is low in the tap.

These are all simple methods to get a handle without going over board and spending more time than the question is really worth.
GH is measured in 18ppm increments, more than most K+ estimations.

I'm not precisely sure the analysis for GH booster to tell the truth, but I alos know it's not critical knowing that either.

If it makes you feel a bit uneasy, you can spend more on SeaChem's, it's got the guaranteed analysis there, home made GH booster does not.
But it's 10x cheaper.

You can make your own also(my choice), then you know(if you feel it's important, which, to tell the truth, no, it's not, unless you want to do experiments etc)

As long as you add 3:1 Ca:Mg from a GH booster, and you have enough for a given rate of growth, then there's little to worry over.

Regards,
Tom Barr