Reef Chemistry Question of the Day #282: Temperature Effects on Parameters

[Randy Holmes-Farley]

Reef Chemistry Question of the Day #282

Suppose your coral reef aquarium is chugging along nicely at 80 degrees F.

You withdraw a sample to run some tests, and the temperature drops to 72 degree F before you are ready.

Which of the following parameters will NOT have changed as the temperature changes from 80 to 72 degrees F (only considering the temp change, not anything else that may be happening, such as gas exchange with the air). Note that any change meets the question criteria. For example, an alk change from 7.4 dKH to 7.401 will count, even if it might still be written as 7.4 dKH.

1. Nitrate at 8 ppm
2. The salinity at 35 ppt
3. pH at 8.1
4. Alkalinity at 7.4 dKH

You can pick more than one answer. At least one is correct (no change at all) and at least one is wrong (will change to some extent).

Good luck and don't be shy guessing. This is not an easy one.

Previous question of the day:

Reef Chemistry Question of the Day #281: Alkalinity You May Not See

Reef Chemistry Question of the Day 281 All of the following are incorporated into commercial supplements. Which of the following will not boost alkalinity in a normal reef tank with regular dosing? 1. Calcium acetate 2. Calcium formate 3. Calcium polygluconate 4. Calcium carbonate 5. Calcium...

www.reef2reef.com

 

[Sisterlimonpot]

My guess is salinity

 

[Pico bam]

Salinty. Possibly nitrate?

 

[DanyL]

I would say Nitrate will not change.
Simply because I know all the others are affected by temperature, though I don't know to what extent in this example.

 

[Randy Holmes-Farley]

I'll give a possibly surprising hint later today. lol

 

[Pico bam]

I'll give a possibly surprising hint later today. lol

Don't leave me hanging randy lol! If not including gas exchange from the air only temp change wouldn't this cause a chain reaction of several of several of them?

 

[90's reefer]

Ph

 

[Randy Holmes-Farley]

Don't leave me hanging randy lol! If not including gas exchange from the air only temp change wouldn't this cause a chain reaction of several of several of them?

The hint needs to wait a bit, because it puts the focus on a unexpectedly important part of the question. lol

 

[Pico bam]

The hint needs to wait a bit, because it puts the focus on a unexpectedly important part of the question. lol

Dang it now I'm all fired up about science

 

[Miami Reef]

Are you asking if the temperature affects the testing process of the parameter, or are you asking if temperature will effect parameter in solution?

 

[Pico bam]

Are you asking if the temperature affects the TESTING process of the parameter, or are you asking if temperature will effect parameter in solution?

Yea this

 

[DanyL]

I would say Nitrate will not change.
Simply because I know all the others are affected by temperature, though I don't know to what extent in this example.

Actually, I'm adding Salinity at 35ppt to the list.
So both Nitrate at 8 ppm and salinity at 35 ppt will not change.

The reasoning behind it is that while the tests themselves can be influenced by temperature, it can be corrected mathematically and both ppt and ppm are total parts found in the water. Without evaporation, gas exchange or any other change they'll still have the same concentration.

 

[gbroadbridge]

Reef Chemistry Question of the Day #282

Suppose your coral reef aquarium is chugging along nicely at 80 degrees F.

You withdraw a sample to run some tests, and the temperature drops to 72 degree F before you are ready.

Which of the following parameters will NOT have changed as the temperature changes from 80 to 72 degrees F (only considering the temp change, not anything else that may be happening, such as gas exchange with the air). Note that any change meets the question criteria. For example, an alk change from 7.4 dKH to 7.401 will count, even if it might still be written as 7.4 dKH.

1. Nitrate at 8 ppm
2. The salinity at 35 ppt
3. pH at 8.1
4. Alkalinity at 7.4 dKH

You can pick more than one answer. At least one is correct (no change at all) and at least one is wrong (will change to some extent).

Good luck and don't be shy guessing. This is not an easy one.

Previous question of the day:

Reef Chemistry Question of the Day #281: Alkalinity You May Not See

Reef Chemistry Question of the Day 281 All of the following are incorporated into commercial supplements. Which of the following will not boost alkalinity in a normal reef tank with regular dosing? 1. Calcium acetate 2. Calcium formate 3. Calcium polygluconate 4. Calcium carbonate 5. Calcium...

www.reef2reef.com

Salinity in ppt will not change
Nitrate wont either

 

[dlsorensen]

I say PH and Alkalinity.

 

[Randy Holmes-Farley]

Are you asking if the temperature affects the testing process of the parameter, or are you asking if temperature will effect parameter in solution?

Getting that right is all part of getting the right answer. lol

 

[Randy Holmes-Farley]

OK, we are far enough down the page to give my hint.

At least one of the answers will be different if I had used a different unit of measure that is also commonly used by reefers for that same parameter.

 

[DanyL]

OK, we are far enough down the page to give my hint.

At least one of the answers will be different if I had used a different unit of measure that is also commonly used by reefers for that same parameter.

There are two - SG for salinity and ppt for Alkalinity.

EDIT: ppm* not ppt

 

[Viperdragon]

I say salinity for sure maybs ppm for alk

 

[Randy Holmes-Farley]

Some great answers and rationale!

Consider also the difference between temp effects on a partly volume based measurement vs temp effects on a pure mass based measurement.

 

[DanyL]

There are two - SG for salinity and ppt for Alkalinity.

EDIT: ppm* not ppt

Your hints do help, I think

As far as I know PH is measured as a combination between conductivity and temperature (commonly by a double junction electrode), so if the equation is reversible, one could recalculate it to a different temperature and the result wouldn't change.

Alkalinity on the other hand, is measured by calculating how much acid needs to be added to reduce the ph to a certain level. If the test was already done, then I believe the result couldn't be recalculated based on a different ph base.

If this is the case, then it means that ph wouldn't change either, or rather it could be recalculated after the fact.
By this logic, the only parameter that would be wrong/different is Alkalinity?