First, don't use Zippo. it isn't a pure naphtha product, look for vm&p or shelite. Zippo will leave behind residues.

Second, get pH strips or a meter at hardware, pet, or a pool store, this is help you a lot! you will not need to worry about converting liters and gallons as long as you pH to 2-4.

teks get confusing.. try giving a step by step of what you plan to do on here.