This is the most economical way to buy T.F.R.This will make at least 50lts of std T.F.R.Pour into an empty drum and use the bottom fill method? carefully!.This product is so strong it will bite back.If you have a monster dirty one to clean try this you have been warned!!! It all depends on the job in hand as to how strong or weak you require the product to be.It has been known for some car washes to use it at 40.1.