How to bring down high salinity

[A Toadstool Leather]

My current salinity is 40 ppt and Im unsure how to safely bring it down. All the freswater I have has kalk dissolved in it for top off. My salinity has been really stable though just too high. Should I dilute my water change water?

 

[mitch91175]

My current salinity is 40 ppt and Im unsure how to safely bring it down. All the freswater I have has kalk dissolved in it for top off. My salinity has been really stable though just too high. Should I dilute my water change water?

Best way is to replace the saltwater with fresh RODI.

 

[mitch91175]

If it hasn’t been like that long, just make some fresh water.

 

[Randy Holmes-Farley Verified Community Expert]

If you are sure it really is high, then I'd remove about 1-2% daily and replace with fresh water. That will take 1-2 weeks (1 at 2% change, 2 weeks at 1% changed).

 

[A Toadstool Leather]

If you are sure it really is high, then I'd remove about 1-2% daily and replace with fresh water. That will take 1-2 weeks (1 at 2% change, 2 weeks at 1% changed).

And that should bring it down to around 35 ppt? Wont this bring my mineral levels down?

 

[Sleepydoc]

First, how did it get that high? If you are topping off, it should stay reasonably consistent. If anything, skimmate production being replaced with RO/DI top off water will tend to bring it down. Like Randy said, make sure it's really high first.

How fast do you want to bring it down? If you just continue regular water changes with 35 ppm (or even a touch lower, say 30) water, it should gradually come down. 40 is high, but not that far out of the normal range that I wouldn't think there should be a huge rush to drop it.

 

[A Toadstool Leather]

First, how did it get that high? If you are topping off, it should stay reasonably consistent. If anything, skimmate production being replaced with RO/DI top off water will tend to bring it down. Like Randy said, make sure it's really high first.

How fast do you want to bring it down? If you just continue regular water changes with 35 ppm (or even a touch lower, say 30) water, it should gradually come down. 40 is high, but not that far out of the normal range that I wouldn't think there should be a huge rush to drop it.

My tank is 30 gallons and I do a 5g wc per week. Im just worried doing wc's would be too slow.

 

[Randy Holmes-Farley Verified Community Expert]

And that should bring it down to around 35 ppt? Wont this bring my mineral levels down?

Yes, and it brings down everything equally.

 

[mitch91175]

Just an FYI, I had this happen to me not too long ago and I just changed out 5 gallon buckets of saltwater with RO/DI water until I got my salinity where I wanted it to be. I did it all at once and didn't have anything die on me. With your size aquarium, you may not have to change out that much of salt for fresh. I'd start out with at least 15 gallons, 1 - 5 gallon to completely change out, the 2nd just in case you do have to do a correction, and the 3rd as a standby.

 

[mitch91175]

Just an FYI, I had this happen to me not too long ago and I just changed out 5 gallon buckets of saltwater with RO/DI water until I got my salinity where I wanted it to be. I did it all at once and didn't have anything die on me. With your size aquarium, you may not have to change out that much of salt for fresh. I'd start out with at least 15 gallons, 1 - 5 gallon to completely change out, the 2nd just in case you do have to do a correction, and the 3rd as a standby.

Also make sure to check your ALK/calcium/mag if you do it that way.

 

[A Toadstool Leather]

I should also note that I have not topped of with sw ever, and that my magnesium is kinda high at 1700ppm

 

[Sleepydoc]

What’s your hurry for dropping it down? Is your livestock showing signs of stress or are you treating your anxiety about the number more than anything else? If your Mg is that high, what is the Ca & Alk? Doing a weekly 5 gallon water change with water at 23 instead of 30 will bring it down to normal over about 6 weeks. In general, fish will tolerate a rapid rise in salinity better than a rapid drop. I doubt dropping from 30 down to 25 will cause any issues, but dropping the SG quickly may actually cause more stress than having it where it is.

 

[A Toadstool Leather]

What’s your hurry for dropping it down? Is your livestock showing signs of stress or are you treating your anxiety about the number more than anything else? If your Mg is that high, what is the Ca & Alk? Doing a weekly 5 gallon water change with water at 23 instead of 30 will bring it down to normal over about 6 weeks. In general, fish will tolerate a rapid rise in salinity better than a rapid drop. I doubt dropping from 30 down to 25 will cause any issues, but dropping the SG quickly may actually cause more stress than having it where it is.

Ca is around 440ppm, and the alk is at 7.3. My livestock looks good as ever though.

 

[Martin Kuhn]

Don‘t overreact but let’s first check
- if your salinity is really that high or just a measurement error
- how you managed to get it as high as 40ppm?

Here are some questions to check if your measured 40 ppm can be trustworthy
- which type and exact model of measurement instrument for salinity do you use?
- in case you measure NOT with a refrak: did you measure also the water temperature during the measurement? How high was it?
- describe as good as possible „how“ you are measuring salinity of your tank

———

Here are reasons that might bring salinity up too high
A) the saltwater you use for changing has a too high salinity from begin on
Several reasons to get this:
In General the amount of salt mixed per gal then was too high
Q: which salt mix did you use
Q: how many grams per gal fresh water?
Q: did you ever check the weigh you used to measure the amount of salt you dosed to be accurate?
Q: did you ever check that the fresh water container has exactly as many gals as you assumed?
B) You „had“ the correct salinity in the beginning, but it raised to 40 ppm as your water level (water volume) dropped significantly by evaporation of fresh water and salt is remaining in the system (as a drying out salt water lake)
C) you added something that slowly raises your salinity (eg 2/3 part dosing!!) and DID NOT notice/react on the raising salinity by doing water changes with reduced salinity.
.... you should do that to compensate while 2/3 part dosing !

 

[mitch91175]

What are you using to check your salinity? When I had my issue, I neglected to zero my Milwaukee refractometer and it eventually led to my higher salinity. When I upgraded my Apex and and noticed that it was reading higher conductivity, I thought about the need to reset my refractometer and it was high. I then proceeded with the steps that I mentioned that I did to decrease mine to where I wanted it.

I'd definitely say verify it is accurate first, then go from there.

 

[A Toadstool Leather]

What are you using to check your salinity? When I had my issue, I neglected to zero my Milwaukee refractometer and it eventually led to my higher salinity. When I upgraded my Apex and and noticed that it was reading higher conductivity, I thought about the need to reset my refractometer and it was high. I then proceeded with the steps that I mentioned that I did to decrease mine to where I wanted it.

I'd definitely say verify it is accurate first, then go from there.

I use an atc refractrometer that I calibrate every use with calibration solution. I might check again to be sure.

 

[Martin Kuhn]

Let us know what came out.

If you have a chance to measure your salinity (density / conductivity) also by someone else where you are confident about the measurement tool & skills, I would do so


Depending on your result we will see if there is action recommend

Also, what about your high Mg value?
Any option to 2x check this one ?

 

[Sleepydoc]

Looking at the values you posted, your Ca is normal, your Alk is on the low-ish side and your Mg is extremely high. It’s possible that the Mg is contributing slightly to your high reading, but I don’t think it would explain everything. I assume you are dosing at least Mg? Are you dosing anything else?

 

[A Toadstool Leather]

Looking at the values you posted, your Ca is normal, your Alk is on the low-ish side and your Mg is extremely high. It’s possible that the Mg is contributing slightly to your high reading, but I don’t think it would explain everything. I assume you are dosing at least Mg? Are you dosing anything else?

I was dosing mg and Im letting it go down naturally. My tank is mostly softies so the mg goes down really slowly. I have been bringing my alk up with small baking soda doses.