Can KCl be used for saline solution, instead of table salt (NaCl)?

In short, we don't recommend doing this as the caps are intended to be used with regular table salt.

However, it's possible to use KCl solution. For safety reasons, particularly with skin contact, a concentration of around 1% is recommended. The electrode cap and sponge will not be affected at this concentration.

Smartfones should not be used with KCl due to the material of the headset!