Help me understand Hanna Checker Salinity changes with temperature

[Deep]

Salinity in ppt​

F (C)	1.020	1.021	1.022	1.023	1.024	1.025	1.026	1.027
74.0 (23.3)	28.0	29.3	30.6	31.9	33.3	34.6	35.9	37.2
75.0 (23.9)	28.2	29.5	30.8	32.1	33.5	34.8	36.1	37.4
76.0 (24.4)	28.4	29.7	31.0	32.3	33.7	35.0	36.3	37.6
77.0 (25.0)	28.6	29.9	31.2	32.5	33.9	35.2	36.5	37.8
78.0 (25.6)	28.8	30.1	31.4	32.7	34.1	35.4	36.7	38.0
79.0 (26.1)	29.0	30.3	31.6	32.9	34.3	35.6	36.9	38.2
80.0 (26.7)	29.2	30.5	31.8	33.2	34.5	35.8	37.1	38.5
81.0 (27.2)	29.4	30.7	32.0	33.4	34.7	36.0	37.4	38.7
82.0 (27.8)	29.6	30.9	32.3	33.6	34.9	36.3	37.6	38.9
83.0 (28.3)	29.8	31.2	32.5	33.8	35.2	36.5	37.8	39.2
84.0 (28.9)	30.1	31.4	32.7	34.1	35.4	36.7	38.1	39.4
85.0 (29.4)	30.3	31.6	33.0	34.3	35.6	36.9	38.3	39.6
86.0 (30.0)	30.5	31.8	33.2	34.5	35.8	37.2	38.5	39.8
87.0 (30.6)	30.8	32.1	33.4	34.8	36.1	37.4	38.8	40.1

 

[Randy Holmes-Farley]

Salinity in ppt​

​

F (C)	1.020	1.021	1.022	1.023	1.024	1.025	1.026	1.027
74.0 (23.3)	28.0	29.3	30.6	31.9	33.3	34.6	35.9	37.2
75.0 (23.9)	28.2	29.5	30.8	32.1	33.5	34.8	36.1	37.4
76.0 (24.4)	28.4	29.7	31.0	32.3	33.7	35.0	36.3	37.6
77.0 (25.0)	28.6	29.9	31.2	32.5	33.9	35.2	36.5	37.8
78.0 (25.6)	28.8	30.1	31.4	32.7	34.1	35.4	36.7	38.0
79.0 (26.1)	29.0	30.3	31.6	32.9	34.3	35.6	36.9	38.2
80.0 (26.7)	29.2	30.5	31.8	33.2	34.5	35.8	37.1	38.5
81.0 (27.2)	29.4	30.7	32.0	33.4	34.7	36.0	37.4	38.7
82.0 (27.8)	29.6	30.9	32.3	33.6	34.9	36.3	37.6	38.9
83.0 (28.3)	29.8	31.2	32.5	33.8	35.2	36.5	37.8	39.2
84.0 (28.9)	30.1	31.4	32.7	34.1	35.4	36.7	38.1	39.4
85.0 (29.4)	30.3	31.6	33.0	34.3	35.6	36.9	38.3	39.6
86.0 (30.0)	30.5	31.8	33.2	34.5	35.8	37.2	38.5	39.8
87.0 (30.6)	30.8	32.1	33.4	34.8	36.1	37.4	38.8	40.1

You did not state what you think that table is, but IT IS NOT the specific gravity of seawater as a function of temperature and salinity, and posting such info in such a way is a terrible disservice to the hobby.

Most likely, that is a table of a glass hydrometer reading as a function of temperature when measuring seawater at a temperature other than the intended temperature of the hydrometer. . You need to understand the difference between specific gravity and a hydrometer reading at a temperature other than its intended temperature.

 

[Deep]

You did not state what you think that table is, but IT IS NOT the specific gravity of seawater as a function of temperature and salinity, and posting such info in such a way is a terrible disservice to the hobby.

Most likely, that is a table of a glass hydrometer reading as a function of temperature when measuring seawater at a temperature other than the intended temperature of the hydrometer. . You need to understand the difference between specific gravity and a hydrometer reading at a temperature other than its intended temperature.

Okay got it, I was under the impression that the hydrometer unit measure was Specific Gravity. Maybe not.

 

[Randy Holmes-Farley]

Okay got it, I was under the impression that the hydrometer unit measure was Specific Gravity. Maybe not.

It is if you measure at the intended temp of the hydrometer. At any other temperature, it is just a "hydrometer reading".

 

[Frogspon]

I feel more confused after reading these responses..

If my tank is at 78 egrees and I set it to ppt, what do I ideally want it to read? And the ppreading should not fluctuate based on temperature of the water?
is there a chart that I can follow to adjust salinity accordingly to where I’m at?

The temperature fluctuations I’m taking about are from when I first stick the tester in the water, vs when it gets to the actual tank temperature. I see the SG reading start high, and read lower as the temperature warms up to the actual tank temp.

 

[infinite0180]

I feel more confused after reading these responses..

If my tank is at 78 egrees and I set it to ppt, what do I ideally want it to read? And the ppreading should not fluctuate based on temperature of the water?
is there a chart that I can follow to adjust salinity accordingly to where I’m at?

The temperature fluctuations I’m taking about are from when I first stick the tester in the water, vs when it gets to the actual tank temperature. I see the SG reading start high, and read lower as the temperature warms up to the actual tank temp.

35ppt is the goal. My recommendation is this: change your meter to ppt mode, calibrate the meter, place into water, wait for the temp and salinity reading to stabilize, i usually give it a minute after swishing it in the water. The first 30 sec or so you place the meter in the water it is attempting to get a reading and adjust it based on temp. This can take some time, it is not an instant meter. Allow both the temp reading and salinity reading to stabilize. Again, i wait at least a full minute.

 

[Randy Holmes-Farley]

I feel more confused after reading these responses..

If my tank is at 78 egrees and I set it to ppt, what do I ideally want it to read? And the ppreading should not fluctuate based on temperature of the water?
is there a chart that I can follow to adjust salinity accordingly to where I’m at?

The temperature fluctuations I’m taking about are from when I first stick the tester in the water, vs when it gets to the actual tank temperature. I see the SG reading start high, and read lower as the temperature warms up to the actual tank temp.

There should be no confusion. No chart is needed or useful.

The "fluctuations" you report are due to the probe taking time to reach tank temp. The reading is meaningless until the probe is at water temp.