Calcium reactor media ... ARM extra coarse

lReef lKeeper · Feb 2, 2019

To those of you running calcium reactors with ARM EC media ...
What do you run your ph controller at ?? The specs for the media says "The highest solubility of any reactor media (metastable at 8.2)". Am I wrong to assume this means that anything below 8.2 ph will dissolve the media ?? Somewhat new to reactors and this is my first purchase of new media, so please bare with me ...

SeaDweller · Feb 2, 2019

I use reborn, not ARM specifically, and my controller is set for 6.8. Anything above 6.8 will send CO2 to the reactor and thus start dissolving the media. I think you'll have to be below 7 to begin dissolving iirc. I have mine off but water is circulating in it at ph 8.0 and it hasn't dissolved.

lapin · Feb 2, 2019

I too use reborn and my reactor Ph is at 6.6 to 6.7. Never Used ARM

sghera64 · Feb 2, 2019

I keep mine set to 6.6-6.8 pH. I’ve had mine as low as 6.5 with no problems.

Randy Holmes-Farley · Feb 3, 2019

lReef lKeeper said:
To those of you running calcium reactors with ARM EC media ...
What do you run your ph controller at ?? The specs for the media says "The highest solubility of any reactor media (metastable at 8.2)". Am I wrong to assume this means that anything below 8.2 ph will dissolve the media ?? Somewhat new to reactors and this is my first purchase of new media, so please bare with me ...

No, it will not dissolve any media at any rate until the saturation index is below 1, and that is not true at, say, pH 8.1.

lReef lKeeper · Feb 3, 2019

Randy Holmes-Farley said:
No, it will not dissolve any media at any rate until the saturation index is below 1, and that is not true at, say, pH 8.1.

That's what I was thinking ... so I'm not sure how they can that on thier spec data. I appreciate all the help guys.

Randy Holmes-Farley · Feb 3, 2019

Aragonite is "metastable" relative to calcite in seawater or reef tank at most any pH. It doesn't actually claim it will dissolve just because it is metastable (those mean different things).

Rakie · Feb 27, 2019

I was wondering what the highest you can run the pH at is to effectively utilize ARM Extra Course myself -- I currently run mine at 6.85 to 7.0 pH, and that will raise my alk by 3dkh per day (my tank is using a little north of 2 dkh at the moment).

sghera64 · Feb 27, 2019

Have you seen the recent BRS Investigates video on the effect reactor pH and Alk concentration in the effluent?

Rakie · Feb 27, 2019

sghera64 said:
Have you seen the recent BRS Investigates video on the effect reactor pH and Alk concentration in the effluent?

Nope, I have fallen behind on their videos

sghera64 · Feb 27, 2019

Rakie said:
Nope, I have fallen behind on their videos

Here you go:

https://www.bulkreefsupply.com/video/video-category/brs-investigates

kris2001 · Dec 6, 2020

Rakie said:
I was wondering what the highest you can run the pH at is to effectively utilize ARM Extra Course myself -- I currently run mine at 6.85 to 7.0 pH, and that will raise my alk by 3dkh per day (my tank is using a little north of 2 dkh at the moment).

Mind telling what your effluent flow rate into sump is? Tia

I'm new to calcium reactors and I'm using arm I want to know at what point max ph say like 7.2...it slowly starts to melt

kris2001 · Dec 6, 2020

Randy Holmes-Farley said:
No, it will not dissolve any media at any rate until the saturation index is below 1, and that is not true at, say, pH 8.1.

Hey Randy, how do i calculate that saturation index? I'm new to calcium reactor set up and I'm using arm media I want to know what is the maximum pH value which I believe it's in the seven range that it will actually start to melt very slowly? Tia

lapin · Dec 7, 2020

I think it has more to do with the size, shape and how porous the media is. Aragonite should dissolve starting at 7.7 , how much thats the question. Caribsea claims it's metastable (soluble?) at 8.2. I dont know if that is really true in real world conditions. Maybe Randy has the time to add something.

Randy Holmes-Farley · Dec 7, 2020

kris2001 said:
Hey Randy, how do i calculate that saturation index? I'm new to calcium reactor set up and I'm using arm media I want to know what is the maximum pH value which I believe it's in the seven range that it will actually start to melt very slowly? Tia

It depends on the pH, the alkalinity, and the calcium value. It is not an easy DIY calculation unless you can find a calculator online.

Exact saturation of normal seawater with aragonite happens around pH 7.8-7.9.

shane105 · Jan 25, 2021

Randy Holmes-Farley said:
It depends on the pH, the alkalinity, and the calcium value. It is not an easy DIY calculation unless you can find a calculator online.

Exact saturation of normal seawater with aragonite happens around pH 7.8-7.9.

Do you have a recommendation on what media to use in a calcium reactor? Thanks for the help!

lapin · Jan 25, 2021

I use Reborn media. They have changed it in the past year and peoples results are it takes a lower Ph to dissolve now

Randy Holmes-Farley · Jan 26, 2021

shane105 said:
Do you have a recommendation on what media to use in a calcium reactor? Thanks for the help!

I don't have a specific recommendation, no.

JCOLE · Feb 19, 2023

Bump.

I just set up my Octo CR5000D reactor with 4 gallons of ARM extra coarse. Does anyone have experience with this media and what the best pH is to run with it?