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Old 05-15-2018, 12:10 AM
#1
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Dumb Question

Is the salinity of water higher or lower as temperature drops? Meaning if you mix water at 77 degrees and get a reading would that reading be higher or lower at 74 degrees? At what temp do you keep your tanks?

Thanks
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Old 05-15-2018, 01:24 AM
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the temp has no effect on the salinity it’s the evaporation of the water that affects the salinity
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Old 07-11-2018, 04:46 PM
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Temp could effect ph (slightly). I keep my reef tank at 79 degrees (+ or - 1 degree).
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Old 07-11-2018, 04:59 PM
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Tank Temp

Oh, ok. I keep my temp set to 77.7 on my chiller +/-1 degrees I should be fine.
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Old 01-12-2019, 03:52 AM
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if you are using a hydrometer rather than a refractometer the water temperature will have an effect on your reading. Even refractometers say to wait 30 seconds for the temp of the water in the sample to normalize to room temp. Unfortunately, I am not sure which way it will go, but my intuition tells me that since cold water is denser that it will cause the "needle" of a hydrometer to raise more.
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Old 01-12-2019, 07:35 AM
#6
Dre
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Quote:
Originally Posted by nyc reefer View Post
Oh, ok. I keep my temp set to 77.7 on my chiller +/-1 degrees I should be fine.
77.7 is fine. Reef temperatures reange from 70-85 at time. Keep in mind some coral will grow slow in cool waters
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Old 01-12-2019, 06:53 PM
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salinity and temperature are independent, except for the secondary effect of raised water temperature increasing evaporation which was mentioned earlier

think about this. salinity is a measure of the ratio between total dissolved salt weight and pure water weight. temperature decreases density generally (one exception is the phase shift of water from frozen to liquid due to the bent nature of the water molecule -- frozen water displaces more volume and is less dense than standing water just above freezing). the polar nature of water aside, weight is not a measure of volume. So generally speaking salinity doesn't change which variation of temperature with the assumption that there is no evaporation.

The way we measure salinity generally is dependent on temperature.

For example a conductivity probe will always give a reading that is temperature dependent. This is because waters conductivty increases with temperature. A lot of controllers, like my apex, using this type of probe will do the adjustment for you somewhat accurately, but in my opinion not accurate enough. There are a variety of factors that effect this type of measurement.

I have always used one of these https://www.bulkreefsupply.com/milwa...actometer.html . They do a great job and do the temperature adjustment for you. you also can with confidence "zero" the device.

Both analog refractometers and digital refractometer like mine work by analyzing the light emitted through a fluid. Particularly how the light bends as the photons go through and interact with the molecules in your tank water. Since colder temperatures increases density the photons will interact with more salt water molecules per distance travelled. The opposite is true as well. Since bending of the light is the basis of the measurement density can plainly be seen as a variable.


A hydrometers readings also greatly depend on temperature, because they look at the relative density of pure water and your sample. Temperature directly effects density for both pure water and your water with dissolved salts. Although, it is not true that a given change in temperature in both pure water and aquarium water will yield an equal change in density between the two samples.

Keep in mind on a large scale it would be pretty accurate to use scales and a large still on your aquarium water -- it would also be a colossal pain in the butt.

Last edited by willienelson; 01-12-2019 at 07:03 PM..
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Old 01-12-2019, 07:06 PM
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Quote:
Originally Posted by willienelson View Post
salinity and temperature are independent, except for the secondary effect of raised water temperature increasing evaporation which was mentioned earlier

think about this. salinity is a measure of the ratio between total dissolved salt weight and pure water weight. temperature decreases density generally (one exception is the phase shift of water from frozen to liquid due to the bent nature of the water molecule -- frozen water displaces more volume and is less dense than standing water just above freezing). the polar nature of water aside, weight is not a measure of volume. So generally speaking salinity doesn't change which variation of temperature with the assumption that there is no evaporation.

The way we measure salinity generally is dependent on temperature.

For example a conductivity probe will always give a reading that is temperature dependent. This is because waters conductivty increases with temperature. A lot of controllers, like my apex, using this type of probe will do the adjustment for you somewhat accurately, but in my opinion not accurate enough. There are a variety of factors that effect this type of measurement.

I have always used one of these https://www.bulkreefsupply.com/milwa...actometer.html . They do a great job and do the temperature adjustment for you. you also can with confidence "zero" the device.

Both analog refractometers and digital refractometer like mine work by analyzing the light emitted through a fluid. Particularly how the light bends as the photons go through and interact with the molecules in your tank water. Since colder temperatures increases density the photons will interact with more salt water molecules per distance travelled. The opposite is true as well. Since bending of the light is the basis of the measurement density can plainly be seen as a variable.


A hydrometers readings also greatly depend on temperature, because they look at the relative density of pure water and your sample. Temperature directly effects density for both pure water and your water with dissolved salts. Although, it is not true that a given change in temperature in both pure water and aquarium water will yield an equal change in density between the two samples.

Keep in mind on a large scale it would be pretty accurate to use scales and a large still on your aquarium water -- it would also be a colossal pain in the butt.
Also my tank stays between 79-79.5 year round.
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