How to approach higher CA than alk demand

[zenn]

Turns out my system uses calcium more than alk. I have a fairly low CA & alk demand overall. The calcium reactor keeps alk stable, but my CA continues to drop.

My question is, what's the best way to approach adding CA to keep up with demand. I've tried using kalk lately, but that raises kalk levels as well, which means alk starts raising too high. I've also used turbo ca in the past, but I've found that while it affectively raises the CA levels to where I want them, it's not a good supplement to use regularly.

I'm wondering if it's not a magnesium problem...

 

[returnofsid]

Try the Ca portion of Randy's Recipe. Here's a link to it. Depending on your pH, there's 2 recipes to use. One is for tanks that are normally lower in pH and the other is for higher pHs.

http://www.reefkeeping.com/issues/2006-02/rhf/index.php

Here's a link to a great Chemistry Calculator to explain how much of the supplement to use, according to your current levels and target levels.

http://reef.diesyst.com/

 

[DonW]

Turns out my system uses calcium more than alk. I have a fairly low CA & alk demand overall. The calcium reactor keeps alk stable, but my CA continues to drop.

My question is, what's the best way to approach adding CA to keep up with demand. I've tried using kalk lately, but that raises kalk levels as well, which means alk starts raising too high. I've also used turbo ca in the past, but I've found that while it affectively raises the CA levels to where I want them, it's not a good supplement to use regularly.

I'm wondering if it's not a magnesium problem...

What is your Mg?

Don

 

[zenn]

Mg = 1080~1100

Could the mg be too low and causing problems getting my CA up?

Also, I believe you said effluent ph doesn't matter, but i'm starting to suspicion that at a higher ph, the cax media dissolves more alk than CA? Is that possible? It just seems to add waaay to much alk and hardly any ca the way I have it set up now at 20bpm and 200ml/m (effluent ph = 7.4)

 

[DonW]

Mg = 1080~1100

Could the mg be too low and causing problems getting my CA up?

Also, I believe you said effluent ph doesn't matter, but i'm starting to suspicion that at a higher ph, the cax media dissolves more alk than CA? Is that possible? It just seems to add waaay to much alk and hardly any ca the way I have it set up now at 20bpm and 200ml/m (effluent ph = 7.4)

Your mg is low. :lol: No its not even possible.

Don

 

[zenn]

I can bring it up with some epson salts. Then alk and ca will be easier to balance?

Another question, does the CAX add magnesium?

 

[DonW]

I can bring it up with some epson salts. Then alk and ca will be easier to balance?

Another question, does the CAX add magnesium?

Yes and yes. The carx will add very small amounds of Mg. You can bump it capabilities by adding Mg media to the media. The Zeovit stuff is good but IMO to expensive. I'm also not a fan of epsom but it is cheap and easy to get.

Don

 

[zenn]

what do you recommend for a mag additive then? MagFlake?

 

[DonW]

what do you recommend for a mag additive then? MagFlake?

I think there is a recipe to blend your own Mg chloride and Mg sulfate but havent read it. Mag flake is fine as long as you keep up with water changes.
I use natural nigari that comes from japan. I used to use kent but it seems to be going down hill.
http://www.reefwerks.com/index.php?act=viewProd&productId=22

Don

 

[Boomer]

Zen

This is what Don is referring to.

This also has an Mg++ sup
An Improved Do-it-Yourself Two-Part Calcium and Alkalinity Supplement System
http://reefkeeping.com/issues/2006-02/rhf/index.php

Do-It-Yourself Magnesium Supplements for the Reef Aquarium
http://reefkeeping.com/issues/2006-07/rhf/index.php

If you mean CAX as calcium reactor one can add 10 % by vol of dolomite media, which is what Don mentioned for Zeo, which is also just a dolomite. The real issue with dolomite is going to be hit and miss as there are different grades fo dolomite. Some are very rich in Mg++ and some are not. You can not use any dolomite by itself as it will cause the Alk to go through the roof, as it has an extra alk component to it.

 

[Boomer]

Power outage

but i'm starting to suspicion that at a higher ph, the cax media dissolves more alk than CA

I forgot the media is CaCO3 and in short --> Ca++ + CO3-. So there is a release of each. More will dissolve at lower pH usually but there are other factors involved, such as temp and incoming Alk but more could dissolve at a high pH/say. Meaning, if for the sake of argument, the incoming Alk was 1.5 meq/ l , pH 7, it would dissolve more media i.e. Ca++ and CO3-- vs an incoming Alk of 3.5 pH 6.9. The there is the issue is the media aragonite or calcite, as aragonite is more soluble than calcite, but the release is the same 1 Ca++ for each CO3--. Then there is the possible is there is dolomite in this media, although I doubt it based on your Mg++. Dolomite can "fake" one out, as the two components CaCO3 and MgCO3 dissolve at a different rates and being dolomite it may look like the Alk is going up with less Ca++ sup but it is the MgCO3 that is really doing it. So, who's media are you using ?

 

[DonW]

The big genx stuff. Just dead coral.

Don

 

[Boomer]

I was wondering what Zen was using. I think the bigger stuff is better and there seems to be more and more of a trend in that direction.

 

[DonW]

I was wondering what Zen was using. I think the bigger stuff is better and there seems to be more and more of a trend in that direction.

Thats what he is using. The bigger sure is alot easier in terms of avoiding melt down than the arm. The draw back Ive seen so far is just hit and miss phospate levels, but I guess that to be expected and easily delt with.

Don

 

[zenn]

Power outage

but i'm starting to suspicion that at a higher ph, the cax media dissolves more alk than CA

I forgot the media is CaCO3 and in short --> Ca++ + CO3-. So there is a release of each. More will dissolve at lower pH usually but there are other factors involved, such as temp and incoming Alk but more could dissolve at a high pH/say. Meaning, if for the sake of argument, the incoming Alk was 1.5 meq/ l , pH 7, it would dissolve more media i.e. Ca++ and CO3-- vs an incoming Alk of 3.5 pH 6.9. The there is the issue is the media aragonite or calcite, as aragonite is more soluble than calcite, but the release is the same 1 Ca++ for each CO3--. Then there is the possible is there is dolomite in this media, although I doubt it based on your Mg++. Dolomite can "fake" one out, as the two components CaCO3 and MgCO3 dissolve at a different rates and being dolomite it may look like the Alk is going up with less Ca++ sup but it is the MgCO3 that is really doing it. So, who's media are you using ?

Don's right. I'm using the big Gen-X media (CRM?). I've heard good things about it so I went with it instead of arm. The big issue for me is understanding why my calcium continues to drop almost 15-20ppm every day, while my alk increases by 0.5 - 1 dKh per day. Since I'm new at this, i'm doing a lot of learning which is prolonging the time it takes for me to correct the issue. The other problem is i travel a lot so I can only make adjustments every other week.

This new magnesium (Mg++) finding supports the notion that if Mg is raised, my cax (calcium reactor) might be able to keep Calcium and ALK more stable. I'll take your advice and put it to work next week when I'm home. In the meantime, I've resumed kalk dosing through a diy kalk reactor, and I've turned down the reactor. I felt this woudl be more stable while I was traveling. So it'll be interesting to see where everything is at in a week when I return home.

I'll post an update when I return. I appreciate all the help. This calcium reactor thing has turned out to be a journey.

 

[danno14]

DonW And Boomer-- any suggestions for a dolomite media to use that is consistent? Thanks

 

[DonW]

DonW And Boomer-- any suggestions for a dolomite media to use that is consistent? Thanks

I was using the zeo stuff for awhile but I burn through so much media it just wasnt cost effective.

Don

 

[Boomer]

Nobody has really looked at one other than we cold say the Zeo is more consistent. One of the reasons is that not all Dolomite is really Dolomite. In the olden days bags of high quality dolomite was very common but there is almost no suuh thing around anymore It is not that one can not get one, it is just finding a good grade. There are lots of "rock" companies that have high grade Dolomite if one does a search. An assay sheet will tell all. The next issue is that you would propably have to buy a dump truck full of it.