my aquarium salt bottle says 1 tablespoon per 10 gal. i've been confused with the whole water change and adding salt deal. so here is what i've figured out. i need to know if my method for adding salt is right. i start out with 1 table spoon in my 10 gal. thats 100% of the dosage. i did a 30% WC. now the concentration is 70%. then i did another 25% water change. so (.25) x (.7) = (.175). (.7)-(.175)=(.525)= 52.5% of my original dosage. then i did another 25% WC. so (.525)x(.25)=(.131). (.525)-(.131)=(.394)= 39.4% of my original dosage. then i did ANOTHER 25% WC. this is getting old.. so (.394)x(.25)=(.099). (.394)-(.099)=(.295)= 29.5% of my original dosage. so im left with 29.5% of the original 1 tablespoon of salt added to the tank. that means i need to add roughly 70% of a tablespoon of salt.
first off, is this method correct in determining the amount of salt i need? keep in mind i added no salt after all these water changes. i would now like to replace the salt i took.
secondly, am i a complete moron for wasting all that time figuring this out? how do you guys keep track of your salt content??? after a while of not being exact, the salt content must get screwed up eventually resulting in buying an expensive salinity test kit.