Ca, dKH & Mg Question

[CastAway]

I have a relatively new tank, my first, running for just over four months now. It’s 200g in total volume, with a handful of SPS and LPS. I’m running a calcium reactor; a Korallin C-1501 with CaribSea A.R.M. fine media.

In four months the media level has dropped 2-3 inches in the reactor, and my Ca, dKH and Mg levels have been pretty consistent. I’ve had one bout of high dKH which I believe was remedied by my dialing back the rate of effluent from the reactor. Although I have no basis for measure or comparison, I have had what I think may be good coral growth, a monti cap and some birdsnests that have more than doubled in size.

The tank looks great - for what that’s worth. Current values (Red Sea):
Ca = 390
dKH = 9.9
Mg 1280

Here are my questions:

1. Using a calcium reactor alone, no dosing, should I expect all three values to rise and fall in proportion to one another? If I increased the effluent output in the hopes of increasing Ca, should I expect the alk and Mg to follow, increasing proportionally?
2. What is the natural trend when using a Ca reactor alone? Are reactors typically supplemented with dosing of some sort?

In my relative ignorance, my hope in running a Ca reactor in the first place was not to have to dose or balance params manually. Be gentle…

 

[ReefMadScientist]

Think of a seesaw. One side is Alk and the other side is Ca. Mag is in the middle.

If you add Ca, it will drop Alk depending on the amount of Ca you added. The same scenario would happen with Alk.

The key is to increase Mag first as it helps stable the two. Think of Mag as the parent. If you want to increase Calcium, you can do so but go slow and TEST TEST TEST.

Read this for more info

Chemistry and the Aquarium

 

[CastAway]

So then, is a Ca reactor adding only Ca, or, Ca and Mg? Does this mean increasing the effluent will lower my dKH?!? Is it common for Ca reactor users to then dose Mg? Sorry. So confused.

 

[mcarroll]

Think of a seesaw. One side is Alk and the other side is Ca. Mag is in the middle.

If you add Ca, it will drop Alk depending on the amount of Ca you added. The same scenario would happen with Alk.

The key is to increase Mag first as it helps stable the two. Think of Mag as the parent. If you want to increase Calcium, you can do so but go slow and TEST TEST TEST.

Read this for more info

Chemistry and the Aquarium

That only applies when you are adjusting the three parameters individually. All in one, or balanced additives, like a Ca reactor or kalk, etc are already...balanced!

Good info to know though!

So then, is a Ca reactor adding only Ca, or, Ca and Mg? Does this mean increasing the effluent will lower my dKH?!? Is it common for Ca reactor users to then dose Mg? Sorry. So confused.

Your reactor adds all three (and more) and in-balance.

It is typical in all tanks to find alkalinity being used faster than the rest because lots of things besides coral skeletons use carbonates from the water. So making alk adjustments is just as typical.

Hope this helps!

-Matt

 

[ReefMadScientist]

That only applies when you are adjusting the three parameters individually. All in one, or balanced additives, like a Ca reactor or kalk, etc are already...balanced!

Good info to know though!

Yes sorry thanks for adding. I was under the impression the OP wanted to raise Ca and lower Kh.

Yes, once balanced, the amounts per Ca and Kh should be the same. Example: 2 g Ca added / 2g Kh added.

As for Mag, this element is not dosed commonly. But good Mag numbers are to be kept.

 

[Reefing Madness]

That only applies when you are adjusting the three parameters individually. All in one, or balanced additives, like a Ca reactor or kalk, etc are already...balanced!

Good info to know though!



Your reactor adds all three (and more) and in-balance.

It is typical in all tanks to find alkalinity being used faster than the rest because lots of things besides coral skeletons use carbonates from the water. So making alk adjustments is just as typical.

Hope this helps!

-Matt

Only way the Calcium Reactor has anything to do with Magnesium is if you add dolomite to it.

 

[mcarroll]

Maybe not the only way. Though in his case - media+pH - I think the OP will eventually find your prediction of low Mg correct. (Maybe not right away though.)

FWIW, combining media (e.g. ARM Fine + NeoMag) complicates things cuz of differing pH requirements - but it can be done. Just find the right combo of media and pH!

The author-host of the Reef Chemistry Calculator has a nice calcium reactor article. Check it out for lots of details!

It's also very possible that water changes could make up the Mg difference. Magnesium usage is tiny compared to the rate of calcium or alkalinity, so it doesn't usually take much in most circumstances. If not, it's possible you may eventually have to dose some magnesium.

Just FWIW, I dose a heavy-demand stony reef manually (including magnesium) and it still feels like I hardly ever dose Mg and the chems to do it last forever. Seemed like the whole time my reef was growing in that Mg-usage was imperceptible...but I also had an excellent weekly water change schedule (using Reef Cystals) that helped a lot.

-Matt

 

[CastAway]

Thanks guys, this is awesome.

So, assuming my current values are "balanced", albeit a little low, I understand that increasing the effluent output should increase each value proportionately.
And, based on the unique dynamics of my own tank, and alk usage in particular, it sounds like I just need to find my own tanks balance; a trio of optimum values wherein I'm not exceeding any one in particular. I suspect alk will be my limiting factor.

Perhaps I'll start a period of daily testing in trying to raise the values.

I suspect this will be a challenge, as my effluent rate is currently determined by a cheap hospital roller clamp, thwarted by build up in the tubing, and, not enough fine adjustment. I've also just been eye-balling drip rate, not capturing and measuring volume, i.e. mL/min.

Another challenge is the fine control valve on my solenoid and CO2 bubble counting. The difference between 3-4 bubbles per second and a burst that fills my reactor, is infinitesimal. I just hate the thing honestly, but seem to be able to keep my effluent values around 6.5.

Thanks again everyone. Yell if I'm missing something.

Once I find my optimum balance, maybe then is when I should evaluate supplementation or other media. If I can't maintain the balance, then maybe I should consider new/better equipment.

 

[ReefMadScientist]

You are correct. Testing is where its at.

As for another option, I am finally going the 2-part route. I use to add supplements by hand but I wasn't being as stable as I thought. At least now I can have Alk, Ca, Mag, etc. added to my tank precisely to maintain that sweet spot.

 

[mcarroll]

Thanks guys, this is awesome.

So, assuming my current values are "balanced", albeit a little low, I understand that increasing the effluent output should increase each value proportionately.
And, based on the unique dynamics of my own tank, and alk usage in particular, it sounds like I just need to find my own tanks balance; a trio of optimum values wherein I'm not exceeding any one in particular. I suspect alk will be my limiting factor.

Perhaps I'll start a period of daily testing in trying to raise the values.

I suspect this will be a challenge, as my effluent rate is currently determined by a cheap hospital roller clamp, thwarted by build up in the tubing, and, not enough fine adjustment. I've also just been eye-balling drip rate, not capturing and measuring volume, i.e. mL/min.

Another challenge is the fine control valve on my solenoid and CO2 bubble counting. The difference between 3-4 bubbles per second and a burst that fills my reactor, is infinitesimal. I just hate the thing honestly, but seem to be able to keep my effluent values around 6.5.

Thanks again everyone. Yell if I'm missing something.

Once I find my optimum balance, maybe then is when I should evaluate supplementation or other media. If I can't maintain the balance, then maybe I should consider new/better equipment.

All of the issues you just named are just a few of the reasons why I hardly ever recommend a Ca reactor...most exceptions are very large tanks. (Dosing kalk or two-part can be *so cheap* these days.)

The issues you name do have some remedies though, given some cash and headache medicine.

Bubble Counting
A digital bubble counter from aquariumplants.com (various configurations availabe - I think they retail elsewhere now too: try google) will take a lot of the variability out of one piece of your puzzle.

Flow Variation
Since you are controlling flow with a clamp, then consider a Flow-Rite PV-2...it's the only design I know that won't ultimately result in a collapsed tube...at least until buildup in the tubing becomes an issue.

Buildup In The Tubing
I think as long as your effluent flow rate is high enough, the buildup should be lessened or minimized. This has to be in tune with the overall reactor though...which can be limiting. Using larger tubing would at least extend the time between clogs.

I'm sure folks will have some other remedies to offer as well. Hope this helps!

-Matt

P.S. Dosers are not without their headaches...there are just fewer of them. No such thing as a perfect solution. (Yet!)

 

[CastAway]

Thank you very much Matt.

I have a small measuring cup now, and can log mL/min and pH, and am going to test twice daily, log results and make adjustments until I can find a sweet spot.

Thanks again.

 

[CastAway]

I have three days worth of data now, and have been slowly increasing the Ca reactor effluent output and CO2 input. The dKH has gone from 9.9 to 11.0; Ca from 385 to 400 & Mg from 1280 to 1300. I'm currently adding 55mL/min effluent at a pH of 6.6. Just a little bit more and I think I will have the numbers I want, a good feel for this reactor, and an idea of what it may be prudent to dose in the future, if anything. At worst, I hope to see my coralline come on a little stronger as a result of all this, and at best perhaps some increased growth on my SPS. Having dialed it in, I'll be interested to see what happens with the values upon my next 15% water change; concerned they may increase out of range, using the Red Sea Pro at 1.026. Not following it so closely, but I did test pH, which is holding at 8.0 even with the additional CO2, proof I think that it's either off gassing well enough or being consumed in my fuge.

 

[CastAway]

Although I may be experiencing some margin of error in testing, or, an inability to maintain constant output of the reactor, it seems my Mg is low while the Ca and alk are in range now. The Mg actually dropped a little, back to 1280. I'm guessing, based on my tanks current consumption, I may need to dose a little Mg to get where I want. Bought "Ions" which is a Seachem product I think. Will read up and start tomorrow I think.