Help fish health

[neil9999]

Just tested the water and the KH is very low.
The nitrate is up but I do does specialised nutrition daily.
PH 7.5
Ammonia 0
Nitrite 0
Nitrate 10ppm
KH 3 ( my tap water is 10)
GH 12
Phosphate 0 to 0.25

Could the nitrate or low KH have caused the the death of my Geo today or the other issue of flashing and wounds, lumps?

 

[Colin_T]

A nitrate level of 10ppm is not going to kill fish. If everyone had nitrate around 10ppm I would be happy

The KH isn't the problem either. If the KH drops to 0 and the pH suddenly drops, that can kill fish. But when there's some KH and the pH is stabile, it's fine.

The male lacustris rainbow has a sore on his side. You will need to monitor that.

The Geohagus has an internal problem and appeared to be suffering. If it's not eating and can't swim in the water without sinking, then euthanise it.