Synthetic salt Water Cheat

[Michael Calise]

Hi, new to the site and very happy I found it in my early stages of reef keeping. I am sure someone has figured out a brand specific weight to get them 35ppt. I was just curious of the brand and grams used per gallon or 10 gallon etc. Thanks.

 

[wkscott]

Most reefers don't weigh the salt. Generally you use about 1/2 cup per gallon of RO/DI water. You then use a refractometer to measure the salinity and tweak the mixture from there.
Some salt mixes do state weight per liter but you still will need the refractometer to ensure the results.

 

[Michael Calise]

I understand checking my salinity with a refractometer. I was thinking that to make water changes easier if you new the exact weight by using a scale you could take the less accurate cup measurements out of the equation and should be fairly close with out adding and checking? I just have been having to add more than a 1/2 a cup per gallon to achieve my desired results.

 

[wkscott]

Every salt brand is different and I too add just slightly more than 1/2 cup per gallon. You would need a highly accurate scale (probably scientific grade and expensive) to achieve the results that you are looking for. Also, once the bag is open, even if you close it quickly, moisture from the air can change the weight of the salt. In addition, not all batches of salt, even from the same brand, may weigh out identically. Water changes are generally a pain, and there are just no shortcuts to mixing a good batch of synthetic seawater without a refractometer.
If you have a specific brand of salt that you want to use, it's probably best to contact its manufacturer to see if they can supply you with the exact weight necessary.

 

[Myka]

Not only is each brand different, but a fresh bucket may weigh less than a bucket that's been open awhile and has absorbed some moisture from the air. I agree that volume is a better measure for salt mix.

 

[Michael Calise]

Ok makes sense thanks for the quick responses

 

[Randy Holmes-Farley Verified Community Expert]

I understand checking my salinity with a refractometer. I was thinking that to make water changes easier if you new the exact weight by using a scale you could take the less accurate cup measurements out of the equation and should be fairly close with out adding and checking? I just have been having to add more than a 1/2 a cup per gallon to achieve my desired results.

I've not seen any brand specific weights to use. I'm also not sure I see any benefit over volume measurement for this purpose.

 

[donnievaz]

I understand checking my salinity with a refractometer. I was thinking that to make water changes easier if you new the exact weight by using a scale you could take the less accurate cup measurements out of the equation and should be fairly close with out adding and checking? I just have been having to add more than a 1/2 a cup per gallon to achieve my desired results.

As long as you always use the same salt, after a while you get good at knowing exactly how much to put in. I can pretty much nail it at this point without even thinking about it but I always check it with the refractometer.

 

[GMay]

I use a simple kitchen scale to weigh my salt. Red Sea salts say to use 38.2 grams to 1 Liter of water. I have used this with both Red Sea and HW Marine, and on checking with a refractometer it is usually spot on. The other way to do it is 35 grams dissolved ina final volume of 1 Liter will give the correct salinity.

 

[Randy Holmes-Farley Verified Community Expert]

I use a simple kitchen scale to weigh my salt. Red Sea salts say to use 38.2 grams to 1 Liter of water. I have used this with both Red Sea and HW Marine, and on checking with a refractometer it is usually spot on. The other way to do it is 35 grams dissolved ina final volume of 1 Liter will give the correct salinity.

Correct for what? It won't give 35 ppt for most mixes (if that is the goal) since there is substantial moisture in most salt mixes. The magnesium salts typically used in many mixes are half water by weight.

 

[MaddyP]

I use a scale to measure my salt as well. It may not be super accurate but I get a consistent 1.025 when mixing 1.60 lbs of Red Sea (Blue Bucket) into 5 gallons of RODI. If I remember correctly, Red Sea specifies the weight for targeted specific gravity.

As @Randy Holmes-Farley said, salt absorbs water depending on several factors, leaving this method not entirely trustworthy, however, testing with a refractometer after each mix should help to reduce drift given by absorption of water into salt.