Instant ocean salt question

[buxndux]

Hey guys. Just want to say thanks for all the help. Got another question though.

I've been using instant ocean salt for the last two months. The kind that comes in the purple lid bucket. I recently ran out and only got a small bag of the instant ocean salt. Still a purple label and same title. However I mixed this salt the same as the old salt. 2 cups per five gallons. That usually get me around 1.024. Unfortunately I was way low on my salinity so I referred to the package and it's says they recommend 1 1/2 pounds of this salt per five gallons. What the heck? I ended up having to dump about 3 more cups of the salt into my 15 gallon bin to get it up to 1.023. Anyone ever come across this? It seems like the salts are different yet they're marked the same. Guess I'll just stick with the bucket stuff or try out reef crystal.

Any comments are appreciated!

Thanks

 

[Macscale]

If it's a reef tank, you should already have to use reef crystals.

I used to put 2 1/2 cups of salt to get my 5 gallons up to 1.025-1.026

 

[jeffaquarius]

Just a word of caution when taking salinity readings. The water temp should be at 77 deg F (25 deg C) for accurate reading. There is a correction factor when saltwater is below 77 'F. The lower the temp the lower salinity readings you will get and a correction has to be made. Meaning if your saltwater has a temp of 73 'F (23 'C) and your salinity reads 1.022 it has a correction factor of 0.0018 so it becomes 1.0238.

Edit : The higher the temp the higher the correction factor is.

 

[Animal-Chin]

Back to the original post, I've been using instant ocean for about 4 years and it that time I've purchased 2 buckets that mixed differently than every other. Usually it's 2.5 cups for 5 gallons but I've had buckets where it was only 2 cups. I'd think every once in a while a batch is off or something...

 

[Gregcoyote]

Salt is salt, if you measured by weight my guess it's about the same each time. Salt can get compacted or fluffed up so that a cupful might not weight the same each time.

Use reef crystals if keeping corals, otherwise their regular blend is fine for fish.


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[jeffaquarius]

That is true if you only have pure salt. The thing is the salt mix is a mixture of several elements with different weight and proportions.

 

[Maridia]

Just a word of caution when taking salinity readings. The water temp should be at 77 deg F (25 deg C) for accurate reading. There is a correction factor when saltwater is below 77 'F. The lower the temp the lower salinity readings you will get and a correction has to be made. Meaning if your saltwater has a temp of 73 'F (23 'C) and your salinity reads 1.022 it has a correction factor of 0.0018 so it becomes 1.0238.

Edit : The higher the temp the higher the correction factor is.

I don't mean to change the subject, but this interests me... I have a 35 gallon tote in my garage, and I have a water pump that constantly mixes it 24/7. However... It's in the heat of summer right now and my water temp is 92F. My salinity reads 1.023. Does that mean when I cool it down (by basically transporting the water in the house and letting it cool all day and over night.) to do a water change, that the new salinity will be something like 1.020!?

 

[aadair22]

If I'm understanding it correctly, it would go the other way and you would be at 1.025


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[jeffaquarius]

If you have mixed it at the same temp and salinity as with your tank before storing, it should maintain its salinity assuming there is no evaporation. According to this correction factor calculator if salinity is 1.023 with temp of 92 the correction factor is 0.005. So it becomes 1.028 at 70 deg F

Specific Gravity Temperature Correction

.

 

[Flaxon-Waxon]

Lesson learned: don't use hydrometers. Use refractometers...

I will also add that I emailed IO regarding their hydrometer regarding compensating for a temp difference, and they replied that there is no compensating needed. Just my $0.02.


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[jeffaquarius]

Lesson learned: don't use hydrometers. Use refractometers...

I will also add that I emailed IO regarding their hydrometer regarding compensating for a temp difference, and they replied that there is no compensating needed. Just my $0.02.


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In the bucket of IO salt mix you will find that they based their data on how much trace elements you would expect with different salinity at 77*F

 

[Maridia]

If you have mixed it at the same temp and salinity as with your tank before storing, it should maintain its salinity assuming there is no evaporation. According to this correction factor calculator if salinity is 1.023 with temp of 92 the correction factor is 0.005. So it becomes 1.028 at 70 deg F

Specific Gravity Temperature Correction

.

Thanks for the calculator. It explains ALOT!!!!! since my garage is super hot, I test my salinity @1.023, but whenever I checked the salinity in my tank, it was always @1.024, couldn't understand why... But now this makes sense. I will have to be very careful when mixing during the winter. The garage can probably get as low as 40-50F.