just a interesting fact I wanted to add, My cleaner shrimp have now turned kinda green/brown like the garlic juice I use to soak my food in. I guess you really are what you eat, hope I don't start looking like cheeseburgers!
As far as making your own garlic mix I am no expert but do buy galic to cook with and to get a lot of juce/pulp mix would take alot of work and smell and you couldn'tt make much up at a time for risk of spoiling in fridge. The sea chem I have also has vit C added. It was just about $10 and will last probally 2 years with just a couple drops 2-3x daily with food, well worth not having the hassel for me anyway.