No, "soft water" is a bit misleading.

GH and KH are different and plants and fish likely, near as anyone can tell are similar.
So it's namely KH, not GH that influences things in FW systems.

Maybe folks add liberal amounts of GH to their Discus tanks, they get better color, better plant health etc.

10 degrees and some very nice breeding discus with great color and health.

So while in general and from say natural environments, soft water might be the general notion, the specifics are another story.

Also, just because something is found in a certain environment in nature, does not imply that is the best way to raise the fish, cow, chicken, dog, lamb, sheep, hog, wheat, rice etc in a controlled environment.

Otherwise agriculture and horticulture would be based solely on natural system, but they are not, not even close. We get much higher and better production with agriculture than we do from natural systems.

Basing a program based solely on nature is not always the best approach, but many in this hobby are led to believe this, discus folks are certainly not above the fray anymore than reef folks or plant folks.

You have to try things and see.
Then you'll know.

But few do, so they keep playing it safe rather than exploring what works, what does not etc.

You cannot learn about new things unless, well, you try new things
Often such things are inadvertent and you notice it later after you made a mistake. Then you go back and do it on purpose and make sure it was not some other interaction.

Unfortunately, few do this in the hobby.
I often wonder about breeders that do not try new things, they have an ample supply of culls available after all.

Use those as the guinea pigs in the test.
Most of my Discus where originally culls, I raised them up, did not care much about what was said in the past, fed them right, they grew up and looked great, bred many times and where sold for 400$ for 5. Not bad for 3" culls that I paid 5$ each for. GH= 9, Temp = 80-82F, KH= 5.5, weekly 50-70% water change, MH's(see the avartar) and high light, high CO2, EI dosing etc.

Most things that Discus advise against.
That was about 12 years ago.


Regards,
Tom Barr

Thanks for the good advice. My tank's pH is 7.4 when the lights are CO2 are off but goes down to 6.4-6.6 when the lights & CO2 are on. I read on some article that Discus don't like pH swings,how do I avoid the big pH swings ?

One of my tanks has a KH below 20mg/L, what do I add to effectively buffer the water? How can I increase KH? Do I add Seachem's Alkaline buffer?