THE BIG 3: Where to keep your Cal, Alk and Mag in your reef tank?

BRS

How important are keeping Calcium, Alkalinity & Magnesium numbers consistent for you?

  • All three are important to me

    Votes: 311 53.4%
  • Calcium and Alkalinity are all I really care about

    Votes: 103 17.7%
  • I really just watch my Calcium level

    Votes: 4 0.7%
  • I really just watch my Alkalinity level

    Votes: 144 24.7%
  • Other (please explain)

    Votes: 20 3.4%

  • Total voters
    582

Runningfanatic

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I made one out of a 16oz water bottle and ran the intake off the back for fresh air from my skimmer. It made my ph problems go away permanently. 7.8 for months to 8.2 steady in a week. Everything is showing growth now and 30% livelier.
Any chance you have instructions on how to make one? I know I need one, but hesitant to buy one because of reviews I've read about the media they use.
 

Dburr1014

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Ca 420 - 425
Alk 8.5 - 8.8
Mg 1300 - 1350
Ph 7.8 - 8.0 want it to be around 8.3.
Going to make a diy C02 scrubber to ty and bring it up. Did the cup of water outside. It went from 7.81 to 8.19 in an hour.
I had constant problems also. My PH would sometimes dip to 7.8 but mostly stay about 8.1 or so. That is with the skimmer pulling air outside the house. I put my calcium reactor outlet into my skimmer to drive off any Co2 and it is now 8.3+-.1
 

lefkonj

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I try to stay pretty stable and Trident does my testing. Having said that I don't like to chase numbers. The changes for that cause to much volatility in the chemistry. Slow changes are fine.
 

killr66tb

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Alk - 9
Ca - 450
Mg - 1500

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Red Sea manual testing of all 3 performed weekly to ensure Trident readings, after which recalibration to DT water is performed (if needed).
How often do you have to re calibrate
 

MnFish1

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See most successful aquariums have Alk, Calc, & Mg dialed in.

9991DBCA-82C8-4AAE-8C55-919EDFD932FE.jpeg
Disagree. Most reef tanks can merely change a bit of water - and dose Ca and Alkalinity without any miracle device - that COULD fail.
 

MnFish1

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I test Alk 2-3 times a week, cal and Mag 1-2 times a week.
I like to try to keep them at:

alk between 8.6-8.8
Cal between 420-450
Mag between 1350-1400

the closer to the upper end of those ranges is where I’d like to try to consistently keep it
I check alkalinity and ca once a month.
 

sarcophytonIndy

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I used to test all three weekly but now just Alk twice a week and Ca/Mg once every few months. Ca/Mg just vary so slowly (w/ 10% weekly wc) and have such a wide range of acceptable numbers that the corals dont seem to mind. Ca has settled out to slightly under 400ppm and Mg to 1200ppm.

I really wish auto testers like the trident would focus on Alk, PO4, and maybe NO3. Just seems like a waste to have Ca and Mg on an auto tester when they're so stable.

I never test for N03 or P04. But I also feed heavily and harvest large amounts of chaeto from the sump regularly.
 

Tamberav

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I just watch Alk. On average I test it once a week... sometimes two weeks if I am busy and forget, it doesn't vary too much with the doser going.

Ca and Mg don't change much at all so I quit checking them. Gosh it may have been a year since I checked them.

NO3 and PO4 are sometimes important to check. I checked them this month (trying out the new Nitrate checker!) but the last time before that was Dec 2020.
 

See Gee Sea

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1. What do the numbers look like for you when it comes to Calcium, Alkalinity and Magnesium? What's your target?
Ca 420-450​
Alk 9.8-10.5​
Mg 1200 - 1350​

2. How important are these three numbers for you? Do you have a hard time keeping them consistent

Numbers are important but stability even more important whatever the number.​
Swings haven't been as drastic in CA and MG since adding a dosing pump. Alk for me has harder to tune in. I made smaller incremental doses vs. all 30mg at once. My main pump isn't running that fast to move it before it precipitates.​
 

Mr.ReefSafe

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1. What do the numbers look like for you when it comes to Calcium, Alkalinity and Magnesium? What's your target?

I have a Neptune Trident set up, mostly for Alkalinity, but I love that I can monitor all 3 parameters. (Neptune, how about a Trident 2 - Nitrite, Iodine, Phosphate)

Alkalinity I like 9-9.5
Calcium 420-440
Magnesium 1350-1400

2. How important are these three numbers for you? Do you have a hard time keeping them consistent?


Of the 3 Alkalinity is the most important. Even before my Trident I tested Alk 2-3x per day with my hanna checker. As for maintaining the levels, I have no issues. I am always monitoring, and still using my Hanna Alk checker 2x per week and have a Neptune Dos set up to keep things stable.

I don't care what Alkalinity monitor you have, but I highly recommend having one if you have hard corals.
 

ReefGeezer

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My tank doesn't have a lot of demand yet. My last test was a few days ago just for kicks. Alk was about 9.5, Calcium around 450, and magnesium maybe 1400... depending on where the teats' end-points really are... with just ~10% water changes (Red Sea). I test only occasionally right now however.
 

Reef Rhino

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Surprised to see that some never test for Magnesium. I dose Kalk and have seen tank Magnesium fall over time. I boost it up to 1400 with lots of magnesium doses and then see it a few months later fall back to 1200 ....

I see distinct grow spurts, especially Monitipora, when magnesium is raised up again to 1400.

75G Reef.jpg
 
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