Recommended max safe salinity change

[anddak]

Hello,

I am not entirely sure if salinity related questions would go to the chemistry discussion but I couldn't find a more appropriate place.

The question is simple. What is the max safe salinity change allowed when it comes to a water change if I want to increase or decrease overall salinity? I have a 13.5g fluval evo so it's a nano system, currently fish only but will be introducing Softies and LPS in the future along with cleanup crew.

Thank you!

 

[shadesatsetbreak]

For your simple question a simple answer: a little bit at a time.

Some more details might help narrow the answer down. Like where you're at now versus where you want to be. If you're going from 34.9ppt to 35.0ppt, I'd say you're safe to do it in under thirty seconds. But that probably doesn't serve you much.

 

[Randy Holmes-Farley Verified Community Expert]

Hello,

I am not entirely sure if salinity related questions would go to the chemistry discussion but I couldn't find a more appropriate place.

Yes, they should.

The question is simple. What is the max safe salinity change allowed when it comes to a water change if I want to increase or decrease overall salinity? I have a 13.5g fluval evo so it's a nano system, currently fish only but will be introducing Softies and LPS in the future along with cleanup crew.

Thank you!

The answer depends in part on what the current salinity is. In an emergency (say, you accidentally have them in 3 ppt seawater) it is appropriate to go faster than if you are just making a correction.

Most of the time, there is no desire to change salinity quickly. To raise it, replacing evaporated water with seawater goes at a good pace.

 

[piranhaman00]

0.001 every three days is what I do with QT tanks.

Its said critters can handle lowering salinity better than increasing it, if that helps

 

[anddak]

Yes, they should.



The answer depends in part on what the current salinity is. In an emergency (say, you accidentally have them in 3 ppt seawater) it is appropriate to go faster than if you are just making a correction.

Most of the time, there is no desire to change salinity quickly. To raise it, replacing evaporated water with seawater goes at a good pace.

To give you more context I was aiming for 35ppt as a base which I’ve got spot on but after observing the level if evaporation, salinity increased by 0.001 in a week, so from 1.026 to 1.027. So i was thinking, is it safe to poor enough RO water to lower it down to 1.026? Also cause of evaporation I probably should aim for 1.025 as a baseline so after lets say a week of evaporation it’s still 1.026 and not 1.027. How do I go about lowering to 1.025 from 1.026? Or let’s say if I want to lower it to1.024 is it safe to do that with one water change?

 

[Doctorgori]

0.001 every three days is what I do with QT tanks.

Its said critters can handle lowering salinity better than increasing it, if that helps

Yeah IME ancedotally it seems going from high to lower can be less fatal/stressfull than going low to high ... I’m gonna risk more cred by saying big temp differences kill faster than small salinity changes ...

 

[anddak]

For your simple question a simple answer: a little bit at a time.

Some more details might help narrow the answer down. Like where you're at now versus where you want to be. If you're going from 34.9ppt to 35.0ppt, I'd say you're safe to do it in under thirty seconds. But that probably doesn't serve you much.

thank you - I just replied with details to another comment

 

[Dbichler]

I’ve never had issues lowering salinity fast by .002 however raising you have to go slower. Temp swings in my experience only irritate corals and anemones. Stability and a obviously best.

 

[Randy Holmes-Farley Verified Community Expert]

To give you more context I was aiming for 35ppt as a base which I’ve got spot on but after observing the level if evaporation, salinity increased by 0.001 in a week, so from 1.026 to 1.027. So i was thinking, is it safe to poor enough RO water to lower it down to 1.026? Also cause of evaporation I probably should aim for 1.025 as a baseline so after lets say a week of evaporation it’s still 1.026 and not 1.027. How do I go about lowering to 1.025 from 1.026? Or let’s say if I want to lower it to1.024 is it safe to do that with one water change?

35 ppt is a sg of 1.0264 or so, thus you only have to move half as far as you thought. I think 35 ppt is a fine target.

There is nothing wrong with salinity rising to 1.026 to 1.027 over a week, but why not add replacement fresh water more often?

 

[anddak]

35 ppt is a sg of 1.0264 or so, thus you only have to move half as far as you thought. I think 35 ppt is a fine target.

There is nothing wrong with salinity rising to 1.026 to 1.027 over a week, but why not add replacement fresh water more often?

Yeah, I heard 1.0264 (35 PPT) is the sweet spot, I was just worried if it raises above that it will be bad. I only had like a litre and a half evaporation a week - maybe it's a good idea to add a little RO like 2-3 times a week rather than once a week just what you said. The other reason why I wanted to lower it is because a few of my readings were high (I already asked in another post and you answered) and I wanted to keep those in check. I am using the Red Sea Coral Pro Salt and based on what I understood the higher the salinity the higher the other elements such as magnesium or calcium.

 

[Randy Holmes-Farley Verified Community Expert]

Yeah, I heard 1.0264 (35 PPT) is the sweet spot, I was just worried if it raises above that it will be bad. I only had like a litre and a half evaporation a week - maybe it's a good idea to add a little RO like 2-3 times a week rather than once a week just what you said. The other reason why I wanted to lower it is because a few of my readings were high (I already asked in another post and you answered) and I wanted to keep those in check. I am using the Red Sea Coral Pro Salt and based on what I understood the higher the salinity the higher the other elements such as magnesium or calcium.

Most of the tropical ocean is in the 34-36 ppt range. 36 ppt is above sg = 1.027. There's no concern about being a little high.

THis shows a typical sea surface salinity map:

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[BuddyBonButt]

Most of the tropical ocean is in the 34-36 ppt range. 36 ppt is above sg = 1.027. There's no concern about being a little high.

THis shows a typical sea surface salinity map:

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Hey, I went from 1.023 to 1.019 pretty quickly by mistake when acclimating, should I be concerned? it's two clownfish