Got to have something in your local chemist for replacing salts. I use Dioralyte sachets . Basically it’s for replacing the water and salts lost from your body when you have diarrhoea, but I find it works equally as well for those who get thick tide marks of salts on there bibs from a hard days ride!
I match the flavours of Dioralyte to my powered ISO energy mix…all then goes in one bottle, last 22 hour ride I did, I didn’t suffer from any cramps…this was compared to the previous months 12 hour ride in which cramps had started some 10 hours in…