Mixing Salt Properly...

[thekeyofb]

I have a question about mixing salt. I use 5 gallon buckets to do my water changes and Instant Ocean Sea Salt. What amount of salt do I mix with 5 gallons of water to reach 1.022 salinity? Is there a certain formula that I have to use?

[roka64]

I think there are directions on the bag/bucket, it's been a while since I have read how much to use. I have it down to where I know how many cups to add.
One other thing, make sure the water is heated to the correct temp if you are using a hydrometer since they do not compensate for cold water.

[melosu58]

I use oceanic but they use 1/2 cup per gallon or 2 1/2 cups per 5 gallon bucket. I dont know if it`s the same or not but I imagine it`s close.

[thekeyofb]

Unfortunately there are not proper directions on the bag/bucket to instruct anyone to achieve a salinity of 1.022. As a matter of fact, the directions are not specific as to which salinity you will achieve. It simply tells you to add 1/2 cup of Instant Ocean Sea Salt Mix per Gallon of water.

I have finally diluted my aquarium water down to the salinity of 1.022 and I want to keep it that way. So, when I am ready to do a water change, I nee to be able to mix the solution to the exact salinity. So, I ask again. Does anyone know what amount of salt I would need to mix with 5 gallons of water to reach a 1.022 salinity? Is there a certain formula that can be used?

[roka64]

I think it is supposed to give you a range of 1.020 to 1.023 at 75°F per 1/2 cup/gallon of water.
There is no way to tell with 100% certainty without using a calibrated refractometer.

[thekeyofb]

Hmmmm. I guess that would make sense. I will definitely have to invest in a good refractometer. Until then, I guess I will have to dilute as needed. Thanks for your help and input.

[roka64]

This is the refracto I use:
Saltwater Aquarium Salinity & Specific Gravity Testing: Portable Refractometer

[Kurt_Nelson]

I use Reef Crytals, which is more or less Instant Ocean. I mix 2 cups of mix with 3.5 gallons of water to get 1.025 water.

Just using that ratio (2c mix -> 3.5g water = 1.025) would mean that for 5 gallons of water, you'd use 2.5 cups per 5 gallons to get 1.022. BUT...

... as others have said, the only true way to know is with a refractometer, which is one of the best investments you can make in this hobby.

[ccCapt]

There is a really simple solution to your question...and all it takes is for you to make 1 5 gallon batch.
Put your water in the bucket.
Add a few cups of salt and test the SG.
Add more till the proper SG is attained.
Write down how much salt you used.

Now you know, when you use that same brand, it should always use the same amount of salt. FWIW, I never mix salt by volume only. I know about how much salt I need to reach 35ppt (which is the salinity of NSW at most reefs around the world) but I check with a refractometer to be sure.

[thekeyofb]

another great idea.....so, i guess there is no mathematical formula to this huh?

[Kurt_Nelson]

There is... once you know how much salt it takes to get to any SG. For example, if you know it takes 2 cups of salt mix in 5 gallons to get to 1.021, then to get to 1.025 it would be...

2 cups * (25/21) = 2.38 cups

The 25/21 is the ratio of salinities, taking only the last two digits.

But even knowing this, it's still important to test your salinity and not assume you got it right.

[thekeyofb]

thanks alot...that's what i was looking for. i have jus order a refractometer and atleast now, i won't waste so much salt trying to achieve my desired salinity.