Dosing confusion

[Nano Gabe]

So I was thinking about starting dosing. After doing some research I found out the appropriate way was to get a good test kit for alkalinity, calcium and magnesium, which I did I was recommended salifert by fellow reefers on REEF2REEF. So I want to calculate how much of these elements my tank is using on a daily basis so I did a water change waited a few hours tested my water and recorded the results. Then I waited 24h to test again, but my alkalinity and calcium have not changed..... my magnesium actually went up some how..... always here are my results:


2 weeks without water change

1/3/19
7.7 alkalinity
420 calcium
1350 magnesium

Few hours after Water change 12Am 1/4/19

Alkalinity 8.3
Calcium 440
Magnesium 1320

1 day(24h) after water change 12AM 1/5/19

Alkalinity 8.3
Calcium 440
Magnesium 1380 ?How?

So I’m planning on testing in another 24h but if my elements are not fluctuating do I even need to dose?

 

[Ktran350]

I would wait 4 days in between testing. That would give you a better idea. Than you take the difference in each parameter and divide it by 4. That will give you an average of how much your system is taking up per day. Than dose accordingly. You can keep doing this to further dial in your dosing. When did you last test your parameter? Your post said 1/5?

 

[Nano Gabe]

Sorry those dates meant to say 2/4/19 and 2/5/19

 

[Ktran350]

Ok, using today’s numbers wait till Friday to test again. Just make sure your testing time is consistent. Also, did you reconfirm your mag numbers by testing it again? Sometimes a testing error occurs but 1380 is still acceptable. Some run mag at 1400.

 

[JimFuller]

The testing you are doing is good. You may discover that the tank is not ready (needing) dosing. Depending on what you have for corals, water changes may be all that is needed to keep the chemistry balanced.

A light load of lps and softies does not require much dosing and can be handled by water changes. A heavy load of sps and Lps can require a lot of dosing and following.

Once you know where your tank sits. You will have a better understanding how often to test and dose.

As for the Mag tests, that could be testing errors. The steps in the salifert test kits can allow for a bit of error at first. I normally would not get too carried away until you have a number of readings.

Have fun!

 

[Nano Gabe]

I will test again in a few days to see if my tank needs dosing but as far a corals I have a 28g jbj nano cube with about 3 sps, 5 LPS (one very large frogspawn and about 10 or so soft corals like zoa’s, leathers, gsp, etc and 2 large rainbow rose bubble tip anemones.

 

[Ktran350]

You can use this calculator to make a determination of your values after a water change as well: test your water change water values and your current parameters. Plug it into this calculator and it will spit out where you should be at after you complete a water change.

http://www.1728.org/mixture.htm

 

[sde1500]

Magnesium 1380 ?How?

Manual testing error. There is always a level of error in the testing to begin with, so a very slight difference like that isn't worth stressing over. That being said, if you test a parameter and it comes out with an unexpected value, it never hurts to redo the test.