Ah I see. Yeah I don't use a lot of salt but I think I should. The mountain water here is "hard", has excessively low
pH (starts out at 6.8 out of the tap then decreased down to 6.4 with high filter flow, or 6.6 with little to no filter flow,) and has low
salinity. I've been keeping fish in this water for almost 12 years and didn't often have fish diseases, however recently I've noticed a huge increase in deaths recently. The water chemistry hasn't changed that I've seen (6.8 pH, 20
nitrate, 0-0.5
nitrite, 0
ammonia/ammonium.) Maybe it's the increasingly poor genetics of fish? Whatever the case, I've lost 2 fish within the last few days (one was suffering from an odd illness for many months, the other had anchor worms when I got him but I hadn't seen adult worms in months.) I think maybe I could try your salt method?
How do you measure the salinity so precisely? A plastic gravity doodad from
instant ocean or one of the expensive ones you look through?