The state of the corraline is a good canary early warning system that things arnt quite right ???
Like I have said before I belive its the KH ............
Plus every single salt mix is different ,Ive tried 2 parters, back in the day IO Tropic Marin the basic one, Kent, you name it ive tried it,however I always come back to RSPro .
With all other salts ive had to adjust the levels before using with this I never have .
Bear in mind too the age of test kits thier only good for about 3 months , then they can start to lie to you . I use Salifert as I feel thier the most accurate . Of course this does not mean they are :smiley: