Kalk slurry aeration

[Garf]

With ref to @Doctorgori thread a while ago;

https://www.reef2reef.com/threads/pulling-air-through-saturated-kalk.580645/
His thread was based around changing a saturated calcium hydroxide into calcium carbonate by reducing the CO2 content in air passed through it to ultimately reduce CO2 in the tank.

Please correct me if I’m wrong, but a Kalk slurry should increase the capacity and therefore minimise maintenance intervals, as the carbonate precipitated would then be replaced by some of the undesolved kalk, dissolving. I don’t really have a problem with adding some sodium hydroxide to improve efficiency but for now I’ve filled a large bubble lamp with slurry and its doing a grand job (1st day, lol). From what I gather, the dry CO2 media is manufactured by rolling Kalk with sodium hydroxide, to form pellets. I’m not feeding a skimmer with this air, but I am feeding a skimmer pump, which is churning away in the sump.

Been meaning to try this for a while and it’s been a few months since I messed with something that didn’t need messing with, so there you go, lol

 

[Randy Holmes-Farley Verified Community Expert]

lol

yes, a high pH solution makes a nice scrubber. It can be sodium hydroxide to win by higher pH, converted more of the CO2 to carbonate and bicarbonate, or with calcium hydroxide, converting more CO2 into calcium carbonate.

I’m not sure which works best in the sort of device setups we use.

 

[Garf]

lol

yes, a high pH solution makes a nice scrubber. It can be sodium hydroxide to win by higher pH, converted more of the CO2 to carbonate and bicarbonate, or with calcium hydroxide, converting more CO2 into calcium carbonate.

I’m not sure which works best in the sort of device setups we use.

Thought I’d make an effort to increase pH (can’t see any harm in that) without screwing with the Alk., Been there, won’t be doing that again. Currently (day one) lights off for 5 hrs, pH ain’t dropped below 8.3. How do I apply for a patent :) Might be able to by a bubble lamp from China for £20, slap a fish sticker on it and charge £60. And then there’s the special high pH additives to absorb carbonic acids. I could be a millionaire by Christmas.

 

[Randy Holmes-Farley Verified Community Expert]

I could be a millionaire by Christmas.

lol

 

[Garf]

I think you will find this CO2 removal method will be standard in years to come. Make me an offer, I’m cheap, lol

 

[Garf]

lol

Back to the reef chemistry stuff. As soon as CO2 reduction is reduced, a simple addition of Kalk to the kiddies bubble lamp, would suffice? I’m not a chemist, just seems logical. I don’t see a reason for ditching the lamp contents until the sand created interferes with the bubbly magic.

 

[Garf]

pH of 8.3 this morning, where normally it’s dipped to 8.1 ish.

The lamp;

 

[Randy Holmes-Farley Verified Community Expert]

Are you stirring that tube, or just letting it settle? If not stirred it may lose effectiveness, and your millions, pretty fast.

 

[Garf]

Are you stirring that tube, or just letting it settle? If not stirred it may lose effectiveness, and your millions, pretty fast.

The bubbles are churning it over, continuously. It all stays in solution. I’ve put a slightly larger air pump in the base than the original one, but the original one was bust.

 

[Randy Holmes-Farley Verified Community Expert]

The bubbles are churning it over, continuously. It all stays in solution. I’ve put a slightly larger air pump in the base than the original one, but the original one was bust.

Great.

Let us know how it works out!

https://pubs.acs.org/doi/abs/10.1021/ef200415p
Although Ca(OH)2 aqueous solution can be effectively used as an absorbent to capture CO2, its performance with highly concentrated CO2 gas mixtures has rarely been reported. Therefore, the present paper investigates the CO2-capture performance of Ca(OH)2 aqueous solution for an about 30% CO2 gas mixture. The Ca(OH)2 concentration in the solution strongly influenced the capture performance of the absorbent. The simultaneous Ca(OH)2 dissolution and CaCO3 production in the absorbent may have substantially hindered the combination of Ca2+ with CO32– in suspension. Therefore, a higher Ca(OH)2 concentration in suspension further reduced the CO2 absorption capacity and produced substantially agglomerated CaCO3 with low crystallinity. In contrast, the Ca(OH)2-saturated aqueous solution had the highest absorption rate and capture ratio among the six investigated absorbents. Its calculated absorption capacity of 3.05 g of CO2 [g of Ca(OH)2]−1 L–1 was 3-fold more than that of 1% Ca(OH)2 suspension solution, which confirmed Ca(OH)2-saturated aqueous solution as the most efficient absorbent for CO2 in a Ca(OH)2 aqueous solution system.

 

[Garf]

Great.

Let us know how it works out!

https://pubs.acs.org/doi/abs/10.1021/ef200415p
Although Ca(OH)2 aqueous solution can be effectively used as an absorbent to capture CO2, its performance with highly concentrated CO2 gas mixtures has rarely been reported. Therefore, the present paper investigates the CO2-capture performance of Ca(OH)2 aqueous solution for an about 30% CO2 gas mixture. The Ca(OH)2 concentration in the solution strongly influenced the capture performance of the absorbent. The simultaneous Ca(OH)2 dissolution and CaCO3 production in the absorbent may have substantially hindered the combination of Ca2+ with CO32– in suspension. Therefore, a higher Ca(OH)2 concentration in suspension further reduced the CO2 absorption capacity and produced substantially agglomerated CaCO3 with low crystallinity. In contrast, the Ca(OH)2-saturated aqueous solution had the highest absorption rate and capture ratio among the six investigated absorbents. Its calculated absorption capacity of 3.05 g of CO2 [g of Ca(OH)2]−1 L–1 was 3-fold more than that of 1% Ca(OH)2 suspension solution, which confirmed Ca(OH)2-saturated aqueous solution as the most efficient absorbent for CO2 in a Ca(OH)2 aqueous solution system.

Looks like it’s still working.Tank pH maxed out yesterday at 8.45 (as opposed to the normal 8. 25 to 8.30) and this morning once again, the low was 8.31. I’ll keep this running 24/7 for now to see how long the 4 massive tablespoons of kalk in 2 gallons of water lasts. I’m contemplating turning it off during the day after that and bypassing the reactor to restrict the daytime rise. It appears, no matter what the starting pH of the tank is, the overnight pH normalises to near 8.3.
I’ve access to a calibrated conductivity probe to assess potency of the slurry.

 

[Garf]

For what it’s worth on a pH meter calibrated at 7 and 10, it’s reading 12.7, after nearly 48 hrs, lol.

 

[Garf]

Bubble production dropped last night (and pH a bit) so this morning investigated and found the strange air stone in the lamp was choked off. Decided to drill a hole through it, so basically it’s now the same as running a very long rigid airline to the bottom of the vessel. In the hour or so it took me to figure out what was going on (initially I thought the air pump had become weak) tank pH reduced considerably, so I suppose that proves the Kalk effect is real. Maintenance will probably require periodic used of a tiny drill bit, guess I’ll find out how often, soon, lol

 

[Garf]

Single point bubbleness seems to work just as well as the aerator. I won’t post any further updates on the chemistry forum, this is more of a DIY thing now. Over and out.

 

[Randy Holmes-Farley Verified Community Expert]

Glad its working out!

Maybe folks can stop buying expensive scrubber media. :)

 

[Garf]

Glad its working out!

Maybe folks can stop buying expensive scrubber media. :)

If BRS wanna pay me a million to shut up, mission accomplished.

 

[taricha]

pH of 8.3 this morning, where normally it’s dipped to 8.1 ish.

The lamp;

So you are pulling normal indoor air through a Kalk slurry, the air goes into a "skimmer pump" you say, so in principle it could just be the airline into a skimmer?
Or is that not quite what's going on?

 

[Garf]

So you are pulling normal indoor air through a Kalk slurry, the air goes into a "skimmer pump" you say, so in principle it could just be the airline into a skimmer?
Or is that not quite what's going on?

Yeah, but don’t know how well a skimmer would work in producing skimmate, especially with slightly pressurised air entering it. The bubble lamp lid is not air tight so if I turn the bubble lamp pump off a skimmer pump should draw in untreated room air, however. Pic at 0830 this morning with the 2 little dogs in the same room and zero photosynthesis at night;

 

[taricha]

I get what you mean with the Bubble lamp now. There's a pump that constantly mixes the air in that tube with the kalk slurry. So then air that gets pulled in to be mixed with the aquarium water has been thoroughly mixed for some time in the bubble tube first.
Very nice results.

 

[Doctorgori]

…and they dismissed at my (our) attempts at REAL science ….
:p:p …. hopefully this will save us some money
thanks for inventing/improvising/posting