Hello Pat,
I thought I have explained both? 1) Whirling and darting and 2) Stiffness of the body which means seizer?helps to explain one of the two behaviors I have seen. One is the hard, strong darting I have seen. The other is the discus is rigid, curled in a C with its body and appears to be having a seizer.
I am confused as to metric and lbs....so just do the dose I recommended and convert it yourself....with whatever brandname metro...... I am sure Jeff can help and recommend.
Yes, you can continue with salt treatment @ 150gms to 200gms per 100 liters of water. That should be sufficient to replenish and prevent dehydration if there is wound and is leaching of salt and the body is depleting salt.. Salt @ above 300gms per 100 liters of water is not good for the discus in long term and may damage their liver.....while 1kg per 100 liters of water, could permanently damage organs or kill young discus in days.
This is because discus spleen carries less than 1.5ppt of salt. That's why they are not brackish water creature. Guppy spleen salinity is 4ppt and that why they are adapted to brackish water and can thrive in salinity of 8 to 10 ppt of salt.
All the best!
Andrew