Ok... now it has been around 6 days since I find out that my tap is already 9 kH and 12 gH and since then I have stopped totally the use of MgSO4 and Calcium supplement.
I have started higher dose of trace and Fe+3 treatment in form of commercial product, dumping more than what I usually did and add it in small doses every day.
I have not yet see significant growth/recovery on the vals. Some that are good are just ok, but those that are creasing and turning white are shedding. The swordplants are ok actually, the only issue is the tiny leaflets that are sprouting from the aerial stems which does not look at best.
However.... I did notice some of my plants are getting the benefit of less hard water (and definately more trace and Fe+3). Check this out
Look at the tops of this alternanthera(?) (dont look at the bottom as they are victim of all maltreatment in the past). Growing taller and new leaves are satisfactionary.
How about these rotalas? Man I'm surprised to take a good look at them, how they grow so tall (background for comparison) these days while remaining thick-stemmed. The red hue is not there yet though. Only the underise and a bit on the top side are reddish.
But not these sunset hygro... even though they do improve a bit, there are still some that sheds. They are not exploding yet and it makes me sick
Why such invasive weed cannot thrife in the tank? Those much more difficult rotala and althernanthera(?) can do well enough
Could it be KCl? (even though some people assure me that the concentration I'm using is far from dangerous). I have not find any K2SO4 yet as it is extremely difficult to get around here (even from chemical stores and suppliers).
I will resume this experiment and see how plants (and algae) react.
Btw, should I resume with a little bit of MgSO4 - some 5ppm? (Calcium is already strictly out of question I guess)