Has anyone made markings on their 6.5 gallon carboy to mark approximate volume measurement? This would make it a lot easier to make sure you're topping off partial boils with the right amount of fresh water. If anyone has, can you please share your method for calculating the right spot on the glass to mark it off? Thanks.
I just add 1 gallon at a time and then mark the level. I keep doing this until I get to the top of the carboy. I've used sharpies and china markers. Neither one stays permanent. Another option is to use tape. One of those stick on thermometers would be good for one of the markers about mid way up.
I've heard of some folks etching the marks into the glass but this scares me. I'm afraid the carboy will weaken and may break easily if it is etched.