ALK & CAL Fluctuations

[Meehan6587]

Hi All,

I am preparing to dose my tank with Aquaforest +1,+2,+3, and have taken a week to monitor my Alk & Calcium consumption. During my nightly water parameters, I've noticed substantial drops and rises. Please see log below:

1/27: Cal - 410 ppm / Alk 6.8 dKH / PH 7.71
1/29: Cal - 327 ppm / Alk 7.16 dKH / PH 7.67
1/30: Cal - 368 ppm / Alk 7.56 dKH / PH 7.65
1/31: Cal - 421 ppm / Alk 7.36 dKH / PH 7.69
2/1: Cal - 376 ppm / Alk 6.7 dKH / PH 7.65

I've been using Hanna Checker testing. I am not sure if these fluctuations are normal, so I am requesting the help of reef central. Please see details of tank below:

100g Tank
30g Sump
Protein Skimmer
UV Sterilizer
GFO/Carbon Reactor
2x MP40's

Salinity: 1.025
Temp: 78 F

Are these fluctuations normal? I've not done a water change during this testing time, but plan on doing a 30g water change when I finalize my dosing schedule. Can anyone provide me with some insight as to why these fluctuations may be happening? Is it normal? Any information would be much appreciated. I look forward to the responses.

 

[bertoni]

Have you been dosing anything into the tank? I'm not sure what's going on yet.

 

[timnem70]

What's your Magnesium level. Correct me if wrong but having a stable Mag level helps bond the others? I know of my mag is at 1500 (mine usually is) my Alk and PH stay pretty stable.
Again not a chemist, just know it is a really important element and when stable the others fall into line. I dose 2 part Now and again, I have LPS so the Calcium stays pretty stable around 480 or 500.

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[timnem70]

Bertoni is a good resource. Never steered me wrong.

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[outssider]

If you're not dosing anything, it's not possible for alkalinity/calcium to increase. I suspect testing error. either something is wrong with the test kits or your procedure. Hanna and others have videos on y-tube to show how to use their kits.

 

[RobZilla04]

Just chiming in here to mention that I've run Hanna back to back for Alk & Ca a few times in the past two weeks. Each time I do get a difference of up to .3 or .4 on Alk and as much as 20-30 for Ca. After noticing those fluctuations due to either noise or human error I test with Hanna and Red Sea to get a good "range" for the values.

As long as that range is reasonable and within the standard accepted I'm good with that.

 

[tmz]

Fluctuations in salinity could effect the other levels .