Calcium dropping faster than alkalinity?

Shilpan Patel · Jun 3, 2019

Hey guys I’m dosing ESVBionic 2 part, 100mL of each bottle a week.
I’ve been dosing for 4 weeks now into my 100 gallon softie tank with about 20 soft corals in it. I run a skimmer, refugium, hydra lights and partially covered top of the tank but there are some gaps. Pumps agitate the surface water a bit.

I find my calcium drops 7ppm a day and Alkalinity drops 0.3dKh a day (average over a month).
I find dosing the 2 part regularly shoots my alkalinity up to like 9.5 but my calcium only up to 390-400 because it drops down again quickly. So on average my alkalinity stays around 8.1 and calcium around 370-380.

Why am I finding it hard to maintain calcium if they’re supposedly used in equal parts? Is something dropping my calcium more? Or keeping my Alk up?

RobW · Jun 3, 2019

Shilpan Patel said:
Hey guys I’m dosing ESVBionic 2 part, 100mL of each bottle a week.
I’ve been dosing for 4 weeks now into my 100 gallon softie tank with about 20 soft corals in it. I run a skimmer, refugium, hydra lights and partially covered top of the tank but there are some gaps. Pumps agitate the surface water a bit.

I find my calcium drops 7ppm a day and Alkalinity drops 0.3dKh a day (average over a month).
I find dosing the 2 part regularly shoots my alkalinity up to like 9.5 but my calcium only up to 390-400 because it drops down again quickly. So on average my alkalinity stays around 8.1 and calcium around 370-380.

Why am I finding it hard to maintain calcium if they’re supposedly used in equal parts? Is something dropping my calcium more? Or keeping my Alk up?

Make sure your magnesium is in check. It plays a big role in keeping a balance. Test your magnesium and let us know what it is. What target calcium level and alkalinity are you shooting for?

RobW · Jun 3, 2019

Are you manually dosing the 2 part or are you dosing it with dosing pumps?

nrenn · Jun 3, 2019

Following because I have a similar, but opposite, problem here. I am dosing Reef Fusion 1 & 2 to maintain Alk and Ca, and testing with Hanna checkers. The strange thing is I am always adding #2 to hold Alk around 10 dKh, but Ca is always in the 530-540 ppm range. It has been months since I've added #1. I'm not really sure where the alk can be going if the Ca isn't also being depleted. Not sure what Mg measurement is, it is supposedly part of the #1 solution, so that hasn't been getting dosed either. I have a Mg test kit ordered, and new reagents for the checkers (I noticed floaters in the Alk reagent, maybe it is contaminated and giving bad readings)
Everything seems healthy, but not seeing much SPS growth either, except for the various montis which are doing very well. Might toss the Fusion, and go with BRS 2-part soon

Shilpan Patel · Jun 3, 2019

Hello!
Magnesium is 1210. Dosing manually.
Is it ok to add 1 or 2 by itself? The instructions say always add both together in equal amounts.

madweazl · Jun 3, 2019

Shilpan Patel said:
Hello!
Magnesium is 1210. Dosing manually.
Is it ok to add 1 or 2 by itself? The instructions say always add both together in equal amounts.

You can add either individually to hit your desired levels. With that said, you may want to bring your magnesium to at least 1250 to help mitigate precipitation of the calcium (not sure what level is "required" to maintain your desired calcium level but 1210 is fairly low).

Shilpan Patel · Jun 3, 2019

Thank you!

RobW · Jun 3, 2019

Yeah, I usually see people keeping magnesium around 1300-1350

inktomi · Jun 3, 2019

It's also hard to overdose Magnesium, so as long as you're testing for it and not just blindly adding it you should be pretty unlikely to overdo it.

Ike · Jun 3, 2019

It's best to keep dosing in equal parts until one number gets to a point that it's really off. There's also nothing wrong with dosing one of them to get numbers up, but there are better ways to go about it since you'll then be low on one part or another if you do it. If it were me I'd get some calcium chloride from BRS and bump calcium by 50-80 points and still dose equal parts two part. It's likely test variability is playing a role in what you're seeing and that equal parts is really what you should continue to maintain. The calcium suggestion is simply a personal preference to have calcium in the 400-450 range, though a little higher or lower is generally fine.