DIY Kalkwasser reactor...anyone done it?

[BanZI29]

Has anyone actually made their own kalkwasser reactor? I am thinking about it because all the ones out there are so BIG and expensive. I need a small one for my 25gal with a mixer (no more then 1 gal capacity) and not connected to my ATO. I am gonna use a doser.
I was looking at slow RPM motors on Amazon and that's what got me thinking about this.

 

[BanZI29]

also acrylic or glass container? which would be better?

 

[BanZI29]

anyone?

 

[ReefGeezer]

I used a magnetic stirrer and a timer. I made a 6" ID acrylic Reactor that held about 1.5 gallons... my daily evaporation rate. I put the water input near the bottom and the output near the top and routed my solenoid controlled ATO water through it. A timer turned the ATO off for an 2 hours every night. The reactor sat on a magnetic stirrer that ran on a timer. It would run for 5 minutes while the ATO was off. It worked ok. I couldn't load it heavily with Kalk, but adding a little every week did the trick. You could make a smaller version. The key is to have a big enough reactor body to hold a day's worth of evaporation make up water.

 

[Doctorgori]

reefdudes did a youtube where he drilled out a reactor and placed it on top of a magnetic stirrer…
vid ain’t hard to find..actually I think he’s got a few on it

 

[Doctorgori]

here is one… I’m not good at posting vids

 

[a.t.t.r]

I would really like to see the output measurement difference between stirred kalk and kalk just sitting in a container (after the first few days have passed) Considering many autotop offs only dump a small amount of water at a time and the water sits for quite a while in the kalk container I suspect stirring is not all that important.

 

[Randy Holmes-Farley Verified Community Expert]

I would really like to see the output measurement difference between stirred kalk and kalk just sitting in a container (after the first few days have passed) Considering many autotop offs only dump a small amount of water at a time and the water sits for quite a while in the kalk container I suspect stirring is not all that important.

I have the opposite concern. Even with stirring, many reactors do not produce saturated limewater, and many folks are surprised to find out how poorly potent their reactor product is when they actually get to measuring it.

 

[ReefGeezer]

I have the opposite concern. Even with stirring, many reactors do not produce saturated limewater, and many folks are surprised to find out how poorly potent their reactor product is when they actually get to measuring it.

I have some anecdotal data to add. My reactor produced an output with a pH of around 11. I assumed it was close to saturation but not 100%. It worked for my low demand system for a long time. I replaced it with a calcium reactor when it couldn't maintain alk.

 

[Randy Holmes-Farley Verified Community Expert]

I have some anecdotal data to add. My reactor produced an output with a pH of around 11. I assumed it was close to saturation but not 100%. It worked for my low demand system for a long time. I replaced it with a calcium reactor when it couldn't maintain alk.

It's hard to gauge the accuracy of a pH measurement that high unless it is calibrated with a high standard, but if it was really pH 11, it is extremely weak (only about 3% of saturation) since saturated limewater has a pH of about 12.54 at 25 deg C, and the scale is logarithmic.

 

[a.t.t.r]

I have the opposite concern. Even with stirring, many reactors do not produce saturated limewater, and many folks are surprised to find out how poorly potent their reactor product is when they actually get to measuring it.

I agree the output is not saturated especially after the first running however does the added stirring really make any difference or would they both be about the same.

I am no chemist by any means it is the one topic I am horrible with. However I suspect that the remaining powder after the first mixing would be a large portion of calcium carbonate as co2 from the water reacts with it. (Assuming this isn’t a direct to RO hook up in an air tight system) or is my assumption incorrect?

 

[ReefGeezer]

I did use a ph meter that was properly calibrated. I agree it was weak... but it served its purpose for quite a while. Once my LPS and SPS started growing, it was no where near enough. I now have a way too big calcium reactor. At some point between the Kalk and calcium reactor I dosed your two-part recipes.

 

[Randy Holmes-Farley Verified Community Expert]

I agree the output is not saturated especially after the first running however does the added stirring really make any difference or would they both be about the same.

I am no chemist by any means it is the one topic I am horrible with. However I suspect that the remaining powder after the first mixing would be a large portion of calcium carbonate as co2 from the water reacts with it. (Assuming this isn’t a direct to RO hook up in an air tight system) or is my assumption incorrect?

Some will be useless calcium carbonate, but even when that is not true, dissolution is slow and challenging. We had a recent thread asking why it was so hard:

Why is Kalk so hard to dissolve?

I have been using kalk in a reactor off and on for years. I started with an Avast K1 and then moved to a K2. I now run a Geo 8" kalk reactor. I switched from the Avast's after I started monitoring the saturation using an EC probe and found that the reactors would start to lose saturation even...

www.reef2reef.com

 

[Randy Holmes-Farley Verified Community Expert]

I did use a ph meter that was properly calibrated. I agree it was weak... but it served its purpose for quite a while. Once my LPS and SPS started growing, it was no where near enough. I now have a way too big calcium reactor. At some point between the Kalk and calcium reactor I dosed your two-part recipes.

For measuring pH that high, it is usually best to calibrate that high, not at normal values like pH 7 and 10.

Saturated limewater is actually a recognized pH standard at 12.54, and to test saturation by pH ( conductivity is a better way, fwiw), I always recommend measuring the pH of truly saturated limewater (say, 2 tablespoons in a cup of RO/DI) and then see how much lower the test solution is. A drop of 0.3 pH units is about a factor of 2 in potency.

 

[ReefGeezer]

Yep... 7 & 10. I didn't realize the potentcy dropped by that high of a factor. No worries for me though. I have 300 gallons worth of calcium reactor for my 90! It was a great deal.

 

[cmozz]

To measure Kalk saturation with EC, what would you calibrate with? I'm using the Neptune PM2 module with the conductivity probe and calibrated with 53 mS/cm.

The only other option is 6668 uS/cm but that is supposed to be for freshwater.

So needless to say, I'm only get a reading of 2.1 mS/cm currently and frustrated.

 

[Randy Holmes-Farley Verified Community Expert]

To measure Kalk saturation with EC, what would you calibrate with? I'm using the Neptune PM2 module with the conductivity probe and calibrated with 53 mS/cm.

The only other option is 6668 uS/cm but that is supposed to be for freshwater.

So needless to say, I'm only get a reading of 2.1 mS/cm currently and frustrated.

Saturation is around 10.3 mS/cm at 25 deg C (higher at lower temps because more dissolves at lower temps).

If the device needs calibrating, seawater conductivity (53 mS/cm is OK, because the device is always properly pegged at zero (assuming it is not broken; it should always read 0 in air). So you span the value being measured.

That said, you can certainly buy a lower standard, or just make one your self with a massive amount of calcium hydroxide in a small amount of water (not mud though). That will be, for our purposes, about 10.3 mS/cm at 25 deg C. Even if it is lower (or higher), just use that lower value as saturation and the potency is roughly linear with the conductivity below that.