So I recently setup my first salt water tank (Fluval Flex 32 gallon). I had previously had a 55 fresh for about two years. My question related to the python is since you have to know exactly how much you have taken out for a water change, how do you do this when it’s just going down the sink drain? Do you mark the tank some how? Sorry for probably a dumb question but I enjoy using the python for removing the water but just need to figure out a way to know how much I’ve removed so I can put back in the same amount!