Nuun

That's the point. For the first bottle yes, it's a piece of piss, for subsequent bottles on a ride it means carrying around salts and fruit juice.

I ride with two bottles, but sure. I don't really believe you need the recommended concentration if you're also digesting food.

And just using sea salt isn't going to get you a good mixture of electrolytes. You may, of course, not think this is necessary.

Sea salt has;

Sodium
Potassium
Magnesium
Calcium
Chloride

That's exactly the same as nuun and my £20/kg Torq powder. The measurements (and therefore ratios) will differ but are in the same quantity order.

It's not a bad start!