Alkalinity and temperature

[Gabaghoul]

Obviously we all know salinity is very dependent on temperature but I was wondering if Alkalinity is affected in the same proportions.

 

[JimWelsh]

Obviously we all know salinity is very dependent on temperature

Do tell....

 

[Gareth elliott]

Temperature will play a role in determining the ratio of carbonate to bicarbonate.
But I think the net alkalinity will be similar enough that the effect will be hard to measure.

As to salinity, i think our measurement of salinity is what changes. As we use specific gravity to measure salinity, and temperature does play a role in density. But the actual concentrations of the elements in the water have not changed.

 

[Randy Holmes-Farley Verified Community Expert]

To Jim’s point, temperature has very, very little impact on salinity. It does have an impact on some of the ways of measuring it, and each method has its own ways of making needed corrections (if any).

For alkalinity, there is no impact of temperature on alkalinity, or within reason, on most of the ways we measure it (temperature might be used by the Mindstream to get carbonate alkalinity from CO2 and pH.

 

[Randy Holmes-Farley Verified Community Expert]

Temperature will play a role in determining the ratio of carbonate to bicarbonate.
But I think the net alkalinity will be similar enough that the effect will be hard to measure.

As to salinity, i think our measurement of salinity is what changes. As we use specific gravity to measure salinity, and temperature does play a role in density. But the actual concentrations of the elements in the water have not changed.

Right, it will shift the ratio, but that won’t alter the total alk, just the contributions of the different species to the total. If one extra bicarbonate ionizes with an increase in temp, you pick up a carbonate, but also the H+, so total alk is unchanged.

 

[Gabaghoul]

Thanks Randy. I appreciate the help. Its been so cold these last few weeks, mixing water in my garage at 65 or 70 degrees definitely has affected my salinity readings as it does my alkalinity but just wanted to check on the science with you.

 

[Randy Holmes-Farley Verified Community Expert]

You're welcome.

Happy Reefing.