Pre-mix is a vegetable extract liquid with the Deep blue dye. Only sell this in the UK atm. If you after shipping pre mix abroad you could try a different re-seller of our liquids.

I normally do all my mixing of liquids before going in the system. A lot of people do it in there system but i find to do it out side you can mess up as much as you like and not worry about removing it from your system.

I test all my mixes first in normal tap water + dye and once i found the perfect match i then use ultra Pure H20.