Randy Holmes-Farley
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Reef Chemistry Question of the Day #68
There are many decisions that go into designing a reef tank. One is whether to have a sump, and if so, how large.
This question bears on just one aspect of sump size: how it impacts the accumulation of unwanted ions in relation to water changes.
Assume that you have a system with a total water volume of 100 gallons and perform a daily water change of 1 gallon.
Also assume that it has a net accumulation (before the daily water change) of 0.25 ppm of nitrate each day and that this net accumulation does not change over time, except when a water change lowers is.
After 1 year, nitrate has accumulated to a certain level. Which value is closest to that level?
A. 0.4 ppm
B. 2 ppm
C. 24 ppm
D. 180 ppm
Now assume everything else is unchanged, but you increase the sump size so that the total water volume is now 200 gallons (twice as large).
How is the nitrate level after 1 year with the larger sump compared to with the smaller sump? Assume no impacts on nitrate except as directly relate to the increased water volume via the same total amount of nitrate added each day as with the smaller sump, and the same 1 gallon water changes daily.
E. It is higher because the 1 gallon water changes are less efficient with a larger total water volume
F. It is the same because only the total production of nitrate matters
G. It is smaller because the nitrate is diluted more with a larger total water volume
Feel free to only answer the second part if you want, as that is the main point of the question.
Good luck!
.
There are many decisions that go into designing a reef tank. One is whether to have a sump, and if so, how large.
This question bears on just one aspect of sump size: how it impacts the accumulation of unwanted ions in relation to water changes.
Assume that you have a system with a total water volume of 100 gallons and perform a daily water change of 1 gallon.
Also assume that it has a net accumulation (before the daily water change) of 0.25 ppm of nitrate each day and that this net accumulation does not change over time, except when a water change lowers is.
After 1 year, nitrate has accumulated to a certain level. Which value is closest to that level?
A. 0.4 ppm
B. 2 ppm
C. 24 ppm
D. 180 ppm
Now assume everything else is unchanged, but you increase the sump size so that the total water volume is now 200 gallons (twice as large).
How is the nitrate level after 1 year with the larger sump compared to with the smaller sump? Assume no impacts on nitrate except as directly relate to the increased water volume via the same total amount of nitrate added each day as with the smaller sump, and the same 1 gallon water changes daily.
E. It is higher because the 1 gallon water changes are less efficient with a larger total water volume
F. It is the same because only the total production of nitrate matters
G. It is smaller because the nitrate is diluted more with a larger total water volume
Feel free to only answer the second part if you want, as that is the main point of the question.
Good luck!
.