Salinity

[Lokemer]

Ok so as you may know i have a 72 gallon soon to be marine tank (like within the week) how do i know how much salt should i use, and how should i measure? this is like the one thing i have no idea about

 

[drsquirrel]

Salinity Refractometer

Or if you are being really cheap, Aquarium Hydrometer.

 

[-Nemo-]

Generally half a cup per gallon of water will give you a salinity of 1.024. That's a decent salinity, but the salinity you want will depend upon what you keep. From there you either add or take away salt for the salinity you want. And as the poster above said, use a refract or hydrometer to check.

a higher salinity --> 1.024 or 1.025 <-- is usually desired if keeping corals or inverts
A lower salinity --> 1.021 to 1.023 <-- is usually desired for fish only tanks

 

[ben1987]

cup rule isnt very accurate because it depends how big the cup is

i usually use 35 grams per liter to go to 35ppt @ 26 degrees. But this varies a bit depending on brand. most salts will come with some guidance

 

[Morri]

cup rule isnt very accurate because it depends how big the cup is

i usually use 35 grams per liter to go to 35ppt @ 26 degrees. But this varies a bit depending on brand. most salts will come with some guidance

Same as Ben H2Ocean 35g per litre

 

[injektion]

i think a cup is 250ml according to imperial and metric measurements (respectively)

 

[drsquirrel]

i think a cup is 250ml according to imperial and metric measurements (respectively)

1 US Cup = ~236ml
1 Cup (UK/Imperial whatever you prefer to call it) = 250ml

And as mentioned, these are volumes and not weights (don't assume 250ml of salt weighs 250g).

Considering these are probably some of the most crazy units ever - probably better to stick to SI recognised units

 

[steelhealr]

Sorry to chime in here but please get your terminology correct: salinity and specific gravity are two different measurements. It's best to use them correctly when discussing marine aquariums.

Salinity is a percentage based on dissolved salt in a liquid. Specific gravity is a single number based on dissolved solids/density.

http/www.fishforums.net/index.php?/topic/326168-salinity-and-specific-gravity/

SH

Ooops...almost forgot my manners:



SH

 

[drsquirrel]

Hopefully most people know that 35ppt is only 1.026 at a specific temperature already... although I have seen whole threads asking why 35ppt doesn't equal some specific measurements on their devices (and how some manufacturers have the scales drawn different to each other).


Maybe it's worth linking (Creating) a calculator from somewhere... like here...
Link removed: mod.

Luckily for us Refractometers with ATC (do they even exist without it?) can measure both for us.