I bought this bidon holder at Bever Zwerfsport. It is suitable to hold the 1,5 liter bottles. Now I just have to find the best place to mount it on my bike.

It’s called the “Minoura PET picker” (AB-1500) specially disigned for the 1 and 1,5 liter lemonade bottles. So I can use a cheap PET bottle and when it gets time to clean it, I can just deposit at the supermarket.