This might be in the wrong area but here goes.
I am using Iodopher btf sanitizer, used for sanitizing wine and beer equipment. When you make a batch of this or another type by mixing with water in a big tub, how long will that stay good for? I notice when you first make it, it is brown and as the days have passed the water has gone to clear. Not sure if i can still keep using it or if it quits working. Any advice would be great!