Mixed salt and now showing low salinity.

[brundell88]

Hey everybody. This is my first post so please take it easy on me.

The reason i'm posting is because I just put up a 55 gallon tank and followed the instructions on the instant ocean bag to use 1/2 cup of salt for a gallon of water and its only showing a specific gravity of 1.018. I have added 2 more cups of salt to the water and now I am to 1.022. At this point I am wondering if this is normal for the measurements to be that far off with instant ocean or if I should worry about my hydrometer being off. (used 2 diff hydrometers)

 

[Mike in CT]

Not out of the question for the specific gravity to be that far off just by going by a measuring cup. Might want to check your LFS's water with your hydrometer to see if its in the ballpark.

Welcome to R2R!

 

[brundell88]

Thanks for the quick reply! I just wanted somebody to reasure me that it is possible for it to be that far off. Like I said I checked it with 2 hydrometers and was just a little freaked out by how much extra I'm having to put in.

 

[Mike in CT]

I always try to start out with my water a little low on salt when I first mix it, then add a little more salt as needed. It's a real pain to try to get too much salt out of the water.. Lol

 

[mike007]

1/2 a cup a gallon should give you give to 1.025. Make sure is its completely mixed.Then retest your results.

 

[brundell88]

Yeah its completely mixed. Thanks for the responses

 

[jdl513]

I can't remember the last time I used a measuring cup for salt.

Find it best to slowly add salt to container with a powerhead stirring the water checking it periodically with a calibrated refractmeter as I go.
The goal is to reach the desired salinity without letting undissolved salt crystals accumulate on the bottom.
Too much salt piling up on the bottom can ruin the chemistry of the mixture.

 

[Randy Holmes-Farley Verified Community Expert]

The hydrometers can also easily be off by that much, if they are the swing arm type. Either check them with a standard, or double check with a different device, such as a calibrated conductivity meter or calibrated refractometer.

 

[captainsaquarium]

The hydrometers can also easily be off by that much, if they are the swing arm type. Either check them with a standard, or double check with a different device, such as a calibrated conductivity meter or calibrated refractometer.

I use the conductivity meters all the time. Excellent

 

[mrBananas]

Hey everybody. This is my first post so please take it easy on me.

The reason i'm posting is because I just put up a 55 gallon tank and followed the instructions on the instant ocean bag to use 1/2 cup of salt for a gallon of water and its only showing a specific gravity of 1.018. I have added 2 more cups of salt to the water and now I am to 1.022. At this point I am wondering if this is normal for the measurements to be that far off with instant ocean or if I should worry about my hydrometer being off. (used 2 diff hydrometers)

1/2 a cup a gallon should give you give to 1.025. Make sure is its completely mixed.Then retest your results.

Instructions on IO salt say 1/2 cup per gallon for 1.022. You'll have to add more if you want to achieve 1.025. It's easy for salt to clump and form air pockets so be careful when measuring by volume. If you have a scale you can compare the 1/2 cup measurements to ensure they are evenly measured. Take your hydrometers to the LFS and see if they can compare them to a refractometer on hand. I've "calibrated" mine that way and know that it reads .002 below actual values. As long as the hydrometers as rinsed/cleaned after use they should read consistently.