Trouble dosing ca / Alk

Dan1789 · Jan 16, 2013

I've been having trouble maintaining my Calcium and Alkalinity the past few months. I was dosing by hand (too much I might add) but now I've done a 7 day no dosing test and determined how much of each I'm consuming each day and I have set up BRS dosing pumps. My tank consumes 44mL of Ca and 34 mL of Alk per day. I have them set up to run over 8 hours to deliver the required amount ( Alk at night). Since the test my numbers fell as I didn't dose for a week so I am dosing 61mL of Ca and 44 mL of Alk to slowly raise them, it worked for a week or so then the numbers fell. Here are some of my tests.

12-23-12 (start of no dose)
Ca: 430
Alk: 8.0
Mg: 1425

12-30-12 (end of no dose)
Ca: 400
Alk: 5.15
Mg: 1380

1-3-13
Ca: 425
Alk: 6.72
Mg: 1470

1-7-13
Ca: 390
Alk: 6.83

1-13-12
Ca: 400
Alk: 7.4

1-16-13
Ca: 370
Alk: 6.2
Mg: 1320

Since the dosing test week however I did add a large hammer coral (size of a small football) and 6 small zoa/pally frags. Don't know if that might change my consumption. Should I increase dosing or decrease, I don't want to overdose and precipitate more out of the water. Or should I increase the dosing period from 8 to say 10 hours?

Any advice is appreciated, soon as I think I have it figured out, BOOM!

ritter6788 · Jan 16, 2013

Get all your numbers where you want them to be first. Test and dose everyday. Test everyday (especially alk) and if there is a drop dose a little manually and increase the time of the dosing pumps. As long as you don't have them dosing at the same time and the same spot you shouldn't have precipitation issues.

It will take daily testing and adjusting of the pumps until you get it locked in. Once it's locked in you can slow down on the testing. I'm confident in my dosing pumps and I still test 3 times a week.

Pkunk35 · Jan 16, 2013

Shouldn't 2 part dosing be done in equal parts of both alk and cal to keep everything in balance?

mixer911 · Jan 16, 2013

Pkunk35 said:
Shouldn't 2 part dosing be done in equal parts of both alk and cal to keep everything in balance?

No, alk and calcium are used up in different ratios by your corals. Alk gets used the most.

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Downbeach · Jan 16, 2013

The uptake of Ca and Alk by "stoney" corals, coraline algae, etc. in a reef system is 20 ppm Ca and 50ppm(2.8dKH) Alk(CaCO3), which is a ratio of 2 pts Ca to 5 pts Alk (2:5).

Two part supplements are designed to provide the same ratio's, by dosing in equal amounts of parts a and b. So, yes you should be dosing in equal parts, since they are already compensating for the appropriate ratio of use(2:5).

Saturated kalkwasser also contains this same ratio, @ ~ 800 ppm Ca(2pts.) to 2,000 ppm CaCO3(5pts.).

If you're using a "reef" grade of salt mix, i.e. Reef Crystals, I'd make sure my salinity is right, by measuring it using a calibrated refractometer, or calibrated metering device. If you're using a swing arm type of hydrometer and it's giving you bad information, you may not be adding enough salt mix, which means that you're also not adding enough of the other elements as well, i.e. Ca, Mg, etc. and you'd require more dosing. With normal WC's at the a salinity of 1.026, I've never had to add Mg, using this type of salt mix.

Singlefin · Jan 16, 2013

I would think the amount used is different which each tank. If you have more Sps you will use more ca. Than someone with more Lps. You need to see what your tank consumes and replenish to the numbers you want to achieve. My tank consumes 10ppm ca. And 1 dkh alk a day. I think I dose twice as much ml of alk thank ca.

Downbeach · Jan 17, 2013

Singlefin said:
I would think the amount used is different which each tank. If you have more Sps you will use more ca. Than someone with more Lps. You need to see what your tank consumes and replenish to the numbers you want to achieve. My tank consumes 10ppm ca. And 1 dkh alk a day. I think I dose twice as much ml of alk thank ca.

The amount/volume needed for each system will be different based on that systems particular needs, but the two part systems are designed to be used in equal parts of both a and b. All stoney corals, including SPS and LPS use the same ratio of Ca and Alk, 2pts Ca to 5 pts Alk, to make their skeletal structure.

See, "Balanced liquid or dry supplements", in this article:

How to Achieve Proper Levels of Calcium and Alkalinity in Your Aquarium

and, "advantages", in this article:

Reef Aquarium Care: Balanced Supplements as a Method of Calcium & Alkalinity Supplementation

So, if you look at the directions of any two part system, regardless of the manufacturer, you will find in the directions that they should be dosed in equal parts. Before starting any of these two part systems, you should first get your param's where you want them, i.e. Ca @ 420, Alk @ 9dKH,...or, whatever your preference is, within recommended ranges.

Dan1789 · Jan 17, 2013

I was trying to raise the levels with the dosing pumps, but I think I will set them back to daily consumption rates and use the BRS reef calculator to manually dose to 420 and 8.0. Thank you for the input.

H2O · Jan 17, 2013

Yeah your alk is on the low side try keep it 8-9 when your alk is low your ph go low as well its important to keep the ca alk mag steady with out huge swings or over dosing so testing weekly til you reach the numbers and then you will see what's your daily maintnance dose

Ron Reefman · Jan 18, 2013

mixer911 said:
No, alk and calcium are used up in different ratios by your corals. Alk gets used the most.

It really depends on what you are dosing with. Especially if you are mixing your own calcium, alkalinity and magnesium. Mixing BRS chemicals by their formulas and you will be dosing very close to 50/50. And I think the more mature and stable your tank is, the more likely it is to be close to equal. Understand I'm not saying the corals use equal amounts of cal & alk, just that if you mix them right, you will dose equal amounts.

mixer911 · Jan 18, 2013

Ron Reefman said:
It really depends on what you are dosing with. Especially if you are mixing your own calcium, alkalinity and magnesium. Mixing BRS chemicals by their formulas and you will be dosing very close to 50/50. And I think the more mature and stable your tank is, the more likely it is to be close to equal. Understand I'm not saying the corals use equal amounts of cal & alk, just that if you mix them right, you will dose equal amounts.

Ron is correct. It depends on what u are dosing with. I personally use BRS for alk and other Cal chloride i mix up. So it depends on the mix ratio of the solutions. If done with just one company's formula and mixed to their spec then it would be equal.

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