measuring how much alk/calcium my tank uses

[ahiggins]

Hey all!
So I want to figure out how much alk and calcium my tank actually uses. I have maybe 8 frags of lps/sps and 2 bigger hammer/toadstool.

My thought is to do a water change tonight (Im like 3 weeks late)
Tomorrow, test all parameters.
test every day for 2 weeks with no water changes to see what it "uses"

Is that how its done?
Any advice?

 

[ShellSea]

You may wish to test every two or three days then average it up for daily consumption. Just my 2 cents but there are many on this forum far more knowledgeable than I.

 

[Oscar47f]

Thats pretty much how its done to figure out how much you basically subtract day 2 from day 1 and the left over value is how much was used up in tha 24h hour period. i would do it at the same time on day 1 and 2 to ensure about 24 hours

 

[ksc]

I would just test your dkh every few days. Ca and mag will follow in proportion.

 

[MaiReef]

I am starting to take daily readings in the morning and and/or at night to get a range of readings. I would just test on a daily basis, however I am far from having great knowledge in the area and I just use API. I noticed I am using more than I thought. I am adding a kalk reactor to bump pH, Alk and Calcium. I am goin gto continue to test frequently to see what habits of mine affect which parameters.

 

[Randy Holmes-Farley Verified Community Expert]

You really only need to monitor alk for such a test. Calcium can be determined mathematically.

Calcium drops much more slowly on a percentage basis, so the demand for calcium is harder to determine accurately from a short test.

Also, the higher the alk, the higher the demand for both. So the drop from 11 to 10 dKH is much faster than the drop from 7 to 6 dKH.

 

[ahiggins]

Thanks for all the info guys!
We shall see in a few weeks how it goes. I dont suspect I use all that much but I want to find out

 

[Ewilson]

So would it be better to test for alk over a week period instead of all 3?