Instant ocean salinity?

LordJoshaeus · Sep 18, 2020

Hi everyone! When I had saltwater tanks in the past, I was using standard instant ocean salt for my aquariums...I was using the standard 1/2 cup per gallon and I thought I had a decent specific gravity of 1.023, based off of my hydrometer. HOWEVER, I have since learned that said hydrometers are often unreliable, especially when not regularly cleaned. I am thinking of using instant ocean again when I make my second attempt with saltwater tanks, but first here's a question...when mixed according to the directions on the box, do you guys actually get the stated 1.022 specific gravity listed on the box? If not, what do you get? I was going to use slightly more salt - about 9 or even 10 tablespoons per 4 liters (I know that is slightly more than a gallon, I just find liters more convenient) - than the directions in an attempt to make the setup more comfortable for any corals or other inverts my next tank may have. Thanks

PicassoClown04 · Sep 18, 2020

LordJoshaeus said:
Hi everyone! When I had saltwater tanks in the past, I was using standard instant ocean salt for my aquariums...I was using the standard 1/2 cup per gallon and I thought I had a decent specific gravity of 1.023. HOWEVER, I have since learned that said hydrometers are often unreliable, especially when not regularly cleaned. I am thinking of using instant ocean again when I make my second attempt with saltwater tanks, but first here's a question...when mixed according to the directions on the box, do you guys actually get the stated 1.022 specific gravity listed on the box? If not, what do you get? I was going to use slightly more salt - about 9 tablespoons per 4 liters (I know that is slightly more than a gallon, I just find liters more convenient) - than the directions in an attempt to make the setup more comfortable for any corals or other inverts my next tank may have. Thanks

Hi! I just dump a bunch in. Usually it’s about half a bag of salt for 20 gallons of saltwater at 1.025

mindme · Sep 18, 2020

I just add salt until I get the specific gravity I want, which is 1.026.

LordJoshaeus · Sep 18, 2020

footgal said:
Hi! I just dump a bunch in. Usually it’s about half a bag of salt for 20 gallons of saltwater at 1.025

Were you using one of the bags listed for 50 gallons of water?

92Miata · Sep 18, 2020

Yeah - its somewhere around 1.022 if you follow the directions. (Atleast for RC it is, haven't used straight IO in a while).

I do about 2 3/4 cups to a 5 gallon bucket (which probably has a bit less than 5g) and end up around 1.026 I then add 2.25 grams of sodium bisulfate to bring the alk down out of the insanity range.

Flippers4pups · Sep 18, 2020

LordJoshaeus said:
Hi everyone! When I had saltwater tanks in the past, I was using standard instant ocean salt for my aquariums...I was using the standard 1/2 cup per gallon and I thought I had a decent specific gravity of 1.023. HOWEVER, I have since learned that said hydrometers are often unreliable, especially when not regularly cleaned. I am thinking of using instant ocean again when I make my second attempt with saltwater tanks, but first here's a question...when mixed according to the directions on the box, do you guys actually get the stated 1.022 specific gravity listed on the box? If not, what do you get? I was going to use slightly more salt - about 9 tablespoons per 4 liters (I know that is slightly more than a gallon, I just find liters more convenient) - than the directions in an attempt to make the setup more comfortable for any corals or other inverts my next tank may have. Thanks

I use IO and have for decades. I shoot for the 1/2 cup and adjust up to 35 ppt. I use a refractometer and calibrate it with calibration fluid at 35 ppt. I suggest using a refractometer to achieve 35 ppt.

LordJoshaeus · Sep 18, 2020

92Miata said:
Yeah - its somewhere around 1.022 if you follow the directions. (Atleast for RC it is, haven't used straight IO in a while).

I do about 2 3/4 cups to a 5 gallon bucket (which probably has a bit less than 5g) and end up around 1.026 I then add 2.25 grams of sodium bisulfate to bring the alk down out of the insanity range.

Didn't realize bisulfate had a use in saltwater tanks...I have used it in the past to push the PH down on softwater aquariums (which often did not dip below the high 5's for me in spite of LOTS of tannins from peat moss, leaves, and alder cones, and in spite of TDS in the teens and non existent KH).

PicassoClown04 · Sep 18, 2020

Link to Amazon I always use this stuff

LordJoshaeus · Sep 18, 2020

Flippers4pups said:
I use IO and have for decades. I shoot for the 1/2 cup and adjust up to 35 ppt. I use a refractometer and calibrate it with calibration fluid at 35 ppt. I suggest using a refractometer to achieve 35 ppt.

What do you usually get from just the half cup of IO?

92Miata · Sep 18, 2020

LordJoshaeus said:
Didn't realize bisulfate had a use in saltwater tanks...I have used it in the past to push the PH down on softwater aquariums (which often did not dip below the high 5's for me in spite of LOTS of tannins from peat moss, leaves, and alder cones, and in spite of TDS in the teens and non existent KH).

@Randy Holmes-Farley has a couple articles on here about adjusting salt with it.

You have to let it mix for a bit because it drives pH really low until CO2 offgasses. You can also use muriatic acid.

anthonygf · Sep 18, 2020

92Miata said:
Yeah - its somewhere around 1.022 if you follow the directions. (Atleast for RC it is, haven't used straight IO in a while).

I do about 2 3/4 cups to a 5 gallon bucket (which probably has a bit less than 5g) and end up around 1.026 I then add 2.25 grams of sodium bisulfate to bring the alk down out of the insanity range.

That's weird, I need 4 1/2 cups of RC per 5 gallons to get to 1.025. What's up with that?

Heabel7 · Sep 18, 2020

mindme said:
I just add salt until I get the specific gravity I want, which is 1.026.

This for sure

t5Nitro · Sep 18, 2020

Mine has always been about 2.5 cups per 5 gallons whether it be IO or RC to achieve 1.026 SG.

92Miata · Sep 18, 2020

anthonygf said:
That's weird, I need 4 1/2 cups of RC per 5 gallons to get to 1.025. What's up with that?

Sure your measuring scoop isn't a half cup?

vetteguy53081 · Sep 18, 2020

Salinity will vary with type of water and mainly temperature of water so you want to mix it at similar temperature as the tank

anthonygf · Sep 18, 2020

92Miata said:
Sure your measuring scoop isn't a half cup?

It stinks getting OLD! LOL I just looked at it and is a 1 cup not the 2 cup I somehow thought it was. Been using it for over 2 years and over time your mind exaggerates a little. Been retired now going on 2 years and with that our brains want to retire also. I try to keep my mind/body busy but is hard sometimes. Sorry for the wrong info and thanks for the reply.

anthonygf · Sep 18, 2020

vetteguy53081 said:
Salinity will vary with type of water and mainly temperature of water so you want to mix it at similar temperature as the tank

That is a good Idea, in 5 gallon bucket with 50 watt heater and pump or powerhead for mixing.

excell007 · Sep 18, 2020

Do not rely on what it says on the box, most of the time you need more than what it say. I use it as a ballpark estimate, then measure with a correctly calibrated meter and adjust accordingly. Having said that, after you have done it many times you will know how much salt to add to get to the salinity you need. I still measure it before adding to the tank to be sure, but it is seldom off by more than .2 ppt for a 30G water change.

LordJoshaeus · Sep 19, 2020

Hi everyone! I was able to find - through some research and calculating - how much salinity instant ocean adds to water. First, here's a chart of instant ocean's components I found a while before I started this thread (forgive me...it's quite small);

The bottom of the chart notes that, at a concentration of 38 grams of instant ocean per liter of water, the salinity of that solution is 32 ppt (or 32 grams per liter); a pound and a half of instant ocean is recommended for 5 gallons of water (and the box rated for ten gallons weighs 3 pounds). Some quick calculating thus found that adding the recommended half cup of salt to 4 liters of water (slightly more water than the recommended gallon but in line with how I wanted to measure water) gives a salinity of 27.62 ppm...not high enough for a saltwater tank. Adding 10 tablespoons of instant ocean per that same four liters would give a fairly good (not perfect) salinity of 34.27 ppt.

anthonygf · Sep 19, 2020

LordJoshaeus said:
Hi everyone! I was able to find - through some research and calculating - how much salinity instant ocean adds to water. First, here's a chart of instant ocean's components I found a while before I started this thread (forgive me...it's quite small);

The bottom of the chart notes that, at a concentration of 38 grams of instant ocean per liter of water, the salinity of that solution is 32 ppt (or 32 grams per liter); a pound and a half of instant ocean is recommended for 5 gallons of water (and the box rated for ten gallons weighs 3 pounds). Some quick calculating thus found that adding the recommended half cup of salt to 4 liters of water (slightly more water than the recommended gallon but in line with how I wanted to measure water) gives a salinity of 27.62 ppm...not high enough for a saltwater tank. Adding 10 tablespoons of instant ocean per that same four liters would give a fairly good (not perfect) salinity of 34.27 ppt.

No mention of sulfur. I am having a sample of fresh salt mix for ICP test to check for sulfur. It is getting higher in my reef.