I checked my salinity in my 30g reef tank today

[Tbkopp]

I checked my salinity in my 30g reef tank today and its reading 1.028 Whats the best way to lower it?

 

[Beej1254]

What did you use to measure the salinity? A hydrometer? Refractometer?

Lowing the salinity is as easy as taking some water out of the tank and replacing with fresh RO/DI water(or whatever water you use). You should make sure you do the change slowly.


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[Tbkopp]

Refractometer I like how much more accurate they are and dont cut corners lol

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[Beej1254]

Depending on if you have an ATO that you need to work around or not then you either do or don't need to take water out. In my setup to keep the water level in my return area of my sump where I want it I have to remove water and add fresh to fix high salinity. You could just add fresh water until it's right. Slowly of course.

I was hoping you'd say a refractometer. But be sure that you are waiting long enough for it to temperature adjust. If you had it stored then when you take it out to use it place a water sample on it and wait a minute before looking at the reading. You may or may not get a different reading. Also get some calibration fluid for your refractometer too to make sure it's where it needs to be.


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[54seaweed]

beej got you on the right track

drain a gal replace with fresh ro/di do this once a day ,( do this over a few days)
this needs to be done slowly not to shock your livestock , once you achieve you desired salinity level you can return to your normal water change schedule
I prefer a range of 1.025 myself
lowering your salinity to fast can shock and sometimes kill so slow is your best bet

 

[Jasonrusso]

How did temperature affect salinity?

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[54seaweed]

How did temperature affect salinity?

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Temp doesn't affect salinity in anyway that I know of ,

 

[Beej1254]

Temperature doesn't effect salinity itself but it plays a role in how the instruments that we use to measure function in giving us reliable results.

When I mentioned temperature earlier I wanted to very simply state that if you have an Automatic Temperature Compensation (ATC) refractometer you have to wait for temperatures to equalize before you get an accurate reading.

I can't tell you how many times I tried to measure salinity in my tank with my refractometer and got different readings all within the course of a few minutes. It's important to place a water sample on the prism and let the temperature equalize to get an accurate measure of specific gravity.


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[Tbkopp]

Well its starting to slowly go down i wait roughly about 3 hours after changes to check the salinity

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[PB_Smith]

How did temperature affect salinity?

Temp doesn't affect salinity in anyway that I know of ,

Temperature doesn't effect salinity itself but it plays a role in how the instruments that we use to measure function in giving us reliable results.

what happens is that heat causes things to expand, including water and cold makes things contract. Actually what is happening is the molecules are moving around faster in a hot material and bump into one another creating space between the molecules and force expansion.

Cold materials have much slower molecular motion going on and therefore do not expand and are denser.
It's called Brownian Motion.

It is that difference in the density due to the temperature of the sample that will give different reading.

A warm sample will contain less dissolved solids per drop than a cold sample will due to Brownian motion as described above, and that is why temp is important when measuring specific gravity.

high school science.

 

[Jasonrusso]

If that's the case, then wouldn't you want to measure it at the temperature your tank is at?

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[PB_Smith]

Ideally yes, but we have no control over what temp the hydrometer was calibrated at/for, so we have to make adjustments.
Many refractometers have integrated temp calibration, mine does.
Otherwise you can use charts to determine the specific gravity at various temps.
here is some more info;


Temperature Corrections for Hydrometers by Randy Holmes-Farley - Reefkeeping.com


Salinity and specific gravity guidelines for the saltwater and reef keeper - Algone