How much salt?


New member
I am getting ready to add salt for the first time to my tank. Thus far it has only had RO waitng for the temp to come up. The bucket doesn't really say how much to add. It has instructions for making small amounts salt water. Do I just go by those instructions. My tank is 125 gal w/ 30 gal sump. Thanks


Staff member
RC Mod
You're going to need 1/2 cup for each gallon of water. The best way to do this without creating salt deposits would be, imho, to withdraw a 5 gallon bucket of water from your system, add 2 1/2 cups of salt (I use a pre-marked old cd spindle packet for this job, marked with a permanent pen) and mix for an hour at least with a pump in the bucket. Add it to your tank, draw off another 5 gallons, and repeat, until your total salt addition is 78 half-cups of salt. (Math is not my strong suite. Check me out here.) But that 5gallon at a time addition should both mix your salt adequately not to create a salt lump in your aquarium and gradually increase your tank salinity to 1.024, which is within the good range (1.024-6).


New member
do you have a hydometer or refractometer?

do yourself a favor and don't add salt directly to the tank ever...and if you don't have one of the above go get one, they read the salinity of water
...1/2 cup per gallon is just a estimate as some salts require a little less and some a bunch more than that amount


New member
being you dont have anything in the tank but water, you wont hurt anything by adding the salt to the tank! not a good practice once you have livestock in the tank though. you will need some powerheads in there for flow however. then slowly add the salt to the tank. use the instructions and multiply for your tank size. most the time that will get your salanity in the 1.021-1.023 ballpark, then adjust from there to 1.025. just make sure you have something to test the SG with! i would recommend a refractometer, but i swing arm hydrometer will work for the meantime. they just are not as accurate.


New member
I here so much about RO or distilled water is good for setting up a salt water tank. Has anyone ever tried using aquafina bottled water or is there's something wrong with using that cuz it says on it something about RO purified on the label.


New member
why would you buy aquafina? that would be an expensive water change/tank fill. you can buy an RO unit online for cheap. check ebay.


Premium Member
I use to use aquafina. It worked O.K. but very expensive when its not on sale. Just bite the bullet and buy an RO.