Hey Bro no worries we are all in this together. Anyways don't worry about the ph, hardness, and stuff like that. That's all product driven parameters that manufacturers thrive on to kick out money burning useless products.
My discus do great in city water ph of 7.2 to 7.8.
I never check for ph, the only water parameters I have is from my city public water analysis.
Discus don't care much about water hardness; young discus do really well in hard water.
It is the eggs that is sensitive to hard water.
So you might need an RO unit at breeding time if you got hard water.
It is the bio load and the nitrogen cycle that is important.
You should do 10% straight tap water change daily at same or similiar temperature. I don't know where you get your water but if you smell chlorine in your tap water, then you might want to age it for 24 hours with air bubbles. But it is totally OK to use straight tap if your water does not have a strong chlorine smell. I do straight tap 75% water changes weekly.
For that sick boy, put him in a small separate tank, add salt, and do everything that same above.
He will mostly pull out of it. If not, you got more fish coming, right?
By the way, who are you getting your fish from.
If you want, PM me for a good recommendation.
Good Luck
well im not sure if imma get some right away but sooner or later....and i probably will be gettin from binh