How to measure water

[edc_aquarium]

For my 55 gallon tank i want to put a little sticker on the side that shows me how much water i put out but how do i know where to put the sticker?

 

[ZoWhat]

I'd put the sticker on the outside of the glass ;Nurse

 

[LouisianaReef]

In order to figure out where to place the sticker you would have to measure out the water you have removed from the tank. When I first setup a tank I use a gallon sized pitcher, figure out what roughly 15 % of the water volume is and remove that many gallons and mark the tank on the outside. Next time I do a WC, I simply drain the tank to the mark and I know how much water I need to mix to replace it.

 

[WVNed]

I used a graduated 5 gallon bucket I got at lowes