Calcium Reactor using seltzer instead of co2...

[CaptiveReef]

I 'm working on a calcium reactor that will utilize seltzer water instead of using co2.
I'm going to use Koralith media in the reactor, and add the seltzer water drop by drop. I will run the tank water through the reactor as it is normally. I'm curious on how the seltzer water will effect the media.
I will post pics of the unit when I'm done, and the performance.

CaptiveReef

[Randy Holmes-Farley]

It certainly can be done, but it may be much harder to control the addition of CO2 than with gas addition.

[grim]

The major issue here is you can only add as much seltzer as you have evaporative losses in your tank, otherwise (quite obviously), you'll overflow the system and drop the salinity. Can you even create enough of a pH drop using seltzer without affecting salinity at all? Have you ever calculated the grams of co2 in a bottle of seltzer water to find out exactly how much seltzer your going to need here? I have a feeling your cost in seltzer is going to far outweigh the cost of co2.

Second issue here is the purity of the seltzer. I've never seen any ro/di seltzer, so you've got to run under the assumption that your seltzer water is no better than tap water. I'd be afraid to add tap water to my tank as evap. make up water. Who knows what kind of impurities you might be adding (I know sodium is added to some seltzers to improve taste).

Say for example, I evaporate 3 liters a day, so I can use 3 liters worth of seltzer to provide the co2 to the reactor. Lets just say this just coincidentally (incredibly) is the amount I need to make up for cal and alk demand. At 25 cents a bottle (for the cheap store brand stuff), we're talking 75 cents a day. We're talking over $250 in seltzer a year, not to mention the 1000 bottles I'd need to buy, transport, and dispose of the plastic (I won't even get into the environmental nightmare of this much pollution). Factor in gas, trips to the supermarket, storage space, the fact I'd need to load in 3 bottles a day (it's almost more work than using a 2 part dosing scheme).

Moral of the story. If seltzer-reactors were both economically feasible and a workable design, we'd all be running seltzer-reactors right now.

Give it a shot though, it sounds like a fun DIY project. I'd love to know how much seltzer is actually required to get down to a pH of 6.7 or so on a recirculating reactor of a large enough volume to support a decent sized tank (50-75ml/min @ effluent pH 6.8).

jb

[CaptiveReef]

grim I see what your saying, but I was going to use the seltzer to dissolve the Koralith media, not to use to top off evaporation. As you said it would require bottle after bottle to do this.
With Kalkwasser you have the volume of water that is saturated with calcium, you can easily use this application for top off.
The seltzer reactor will dissolve the media, and I will slow down the main tank water feed so I can get the pH down enough in the reactor.
The finished product I'm hoping will be calcium addition not volume top off, I will use filtered fresh water to top off for evaporation. Using the reactor will be like dosing with a calc/buff agent. I'm going to use a large bottle of seltzer for the first try and it will be gravity fed very slow (drop by drop) into the reactor. I will monitor the calcium and pH levels in the main tank to see if there is an increase in both.
The reactor tube is going to be 20 inches tall 3inch diameter clear acrylic , after some tinkering, I'm looking to get a good dose of calcium per bottle of seltzer water.

Well Randy here is to Science




CaptiveReef

[Randy Holmes-Farley]

The finished product I'm hoping will be calcium addition not volume top off, I will use filtered fresh water to top off for evaporation.

His concern was that you'd become volume limited by the water going in with the seltzer that is necessary for a reasonable amount of dissolution. I think this won't be limiting, but it may depend on exactly how much CO2 is in your soda water (it varies) and how well you get it into the reactor without loosing any CO2 (which may be tricky; I was recently trying to see how much the pH drops when adding soda water to tank water (a few tenths of a pH unit for one teaspoon seltzer per gallon), but the spoon was bubbling as I was measuring it out).

Well Randy here is to Science



let us know what happens.

FWIW, I related this story in a recent article:

Calcium Carbonate as a Supplement (Aragamight; Liquid Reactor)
http://www.advancedaquarist.com/issu...y2002/chem.htm

"At one point I had the bright idea of adding aragonite to seltzer (soda water) bought at the grocery store to really boost the solubility and maybe have a nice, liquid additive. Seltzer has far more carbon dioxide in it than water in contact with normal air (which is why it goes flat when open), and that extra carbon dioxide will cause a great deal more calcium carbonate to dissolve (at 3.5 atmospheres CO2, the solution would contain more than 10 meq/L alkalinity and would be similar to limewater in potency, but much lower in pH). If only I had been able to mix them…… Instead, it ended up a science experiment for the kids, with the added aragonite sand providing a perfect surface for the carbon dioxide to turn into the gas phase and erupt from the bottle as a fountain of water, gas, and sand!"

[CaptiveReef]

Yes the transfer of the seltzer, is going to be tricky. I have been thinking of a way to get the seltzer into a holding bottle without letting any co2 escape.
Also when you drop the temp of seltzer water, the water retains the co2 better.
I'll be back with the results


CaptiveReef

[TANGBOY5000]

My question is why? I'm all for science, but this seems neither practical nor reliable. What is the reasoning behind using seltzer water vs. compressed CO2 gas. My 20lb. bottle costs me $8 to fill and lasts me like a year. The cost of using seltzer not to mention the time spent adjusting and fiddeling with it just seems like too much to me. But if it's just an experiment to see if it could be done then carry on.

[CaptiveReef]

Tangboy5000, you have to experiment!!!! I'm looking to get a calcium dose from this unit, not top off. A bottle of seltzer is about 80 cents, the design I'm trying for is to dissolve the calcium carbonate, with the amount of seltzer per bottle.
My 1st try will be to fill the reaction chamber with media and 1 full bottle of chilled seltzer or enough to cover the media,(cold soda water retains co2 better than warm).
The soda water will be circulated through the media with a small powerhead. At this point I want to see how much of the carbonate will dissolve, then I will feed tank water through the reactor, very slowly to keep the pH from going up inside the reactor.
Yes there will some tinkering, but if I can get the results I'm looking for, then it could be a new way for calcium addition.
Also it would be a smaller unit that could be used for smaller tanks, or for hobbyists that can't get co2 or afford a normal reactor setup.
I have 2 more new designs, an overflow tube that operates like a surface skimmer, and it won't lose it's siphon.
And a filtration/skimmer design that will be installed into a dedicated tank, that will allow to maintain water quality while not dangering fish or inverts in their larval stages.
Making it able to successfully raise the fry through those difficult stages.
I have the materials already, pics will be coming soon.
CaptiveReef

[wise owl]

Hi, ive done this myself but i dosed some DI water up with a soda stream machine i have access too...., mainly because the aragamight powder is pretty crap with normal water and got alot more into solution than just normal water this way....i forget the actuall figures....think it was about 10 times as much...., the trick is to put the powder in AFTER the waters dosed and not before [just get the top on quick !! lol], i did this for a while but then switched over to more conventional calcium supplementation on my nano....,
i did register lower PH than i would have liked doing this but it seems thats the way of things when going the CO2 route...

any other ideas to use up a tub of lousy aragamite would be welcomed !......maybe dissolve it in vinegar ??

paul.

[Gerard Alba]

We will be waiting for the results.

[bergzy]

if you want my koralith media...you can have mine...FREE!!! just pay for shipping. i am not kidding...i hate the stuff.

i set my pH controller to 6.5 and the stuff still does not melt! i am pretty disappointed with the koralith material. i even emailed knop 3 times to see what i was doing wrong...no response.

so if you choose to use the seltzer method and koralith...be prepared to try and melt, literally, rock hard stuff.

why did i not set my pH controller any lower than 6.5? why should i? ARM states that you can set your controller to 7.5. i set mine to 6.75 and getting excellent dissolution. i burn through over an inch of material a week and my ca levels are finally constantly above 360...whereas with the koralith it was NEVER above 320...and this was me addinga ton of tropic marin bio-calcium (btw is not cheap!!!)...so, in other words, the koralith did ZILCH for my calcium levels!!!

keep us posted on your progress and results! hey, you could host a total party with your seltzer stockpile at a drop of a hat!

[CaptiveReef]

I have decided to use CaribSea special grade aragonite reef sand in the reactor. I 'll post what the results are when I fire the unit up.


CaptiveReef

[Shaun Monahan]

Originally posted by CaptiveReef
I have decided to use CaribSea special grade aragonite reef sand in the reactor. I 'll post what the results are when I fire the unit up.


CaptiveReef

I did a simular experiment in '97 with caribsea aragamite(fine powdered CaCo3) on a 150gal heavy stocked reef. After a week of adding a 2 liters of seltzer h2o/day to (1)tsp of aragamite in a bucket, I would test an 1hr after adding solution and couldn't find any change in Ca or alk. I gave up on it.

I did try HCL with a bucket filled with aragonite. I would let the bucket of aragonite sit overnight and degass before adding it to the sump. This experiment was not very scientific as I just eye-balled the amount of acid to aragonite. It worked quite well but the tank would be cloudy for hrs after adding. I also had a P04 issue that I can only assume came from the aragonite I was dissolving(caribsea special grade sea floor). But again, only an assumption. Also, the calcium would be off the chart and a more measurable approach was needed. I quit afte a week because of the constant fooling with, and the cost for the HCL and aragonite.


I would just use a reactor. It is by far cheaper in the long run and you can easily adjust it....

my 2

[MarkM3]

What about generating CO2 by dripping vinegar into baking soda? (the byproduct of which is CO2)

[MarkM3]

Oh yeah, the above mentioned vinegar and baking soda is an extablished method for making CO2 in a freshwater planted tank.

[CaptiveReef]

Originally posted by MarkM3
Oh yeah, the above mentioned vinegar and baking soda is an extablished method for making CO2 in a freshwater planted tank.

This is something I'm going to try, if I can get more co2 production with this combination it could give me better results. I 'm going to try some different ways to add the seltzer for the 1st try just to get some results. The I'll try the vinegar/baking soda combination.
Thanks for the suggestions!!!!!!!!!

CaptiveReef

[AnnArborBuck]

This is something I'm going to try, if I can get more co2 production with this combination it could give me better results. I 'm going to try some different ways to add the seltzer for the 1st try just to get some results. The I'll try the vinegar/baking soda combination.

I had thought of something like this in the past. I was going to go with the yeaast and surgar method, but instead of just plain yeast and surgar I was going to brew Beer or Wine and use the off gassed CO2 from the fermentation. That way, the tank gets it's CO2 and I got my alcohol. Getting married and having kids put an end to that dream.

[CaptiveReef]

Originally posted by AnnArborBuck
I had thought of something like this in the past. I was going to go with the yeaast and surgar method, but instead of just plain yeast and surgar I was going to brew Beer or Wine and use the off gassed CO2 from the fermentation. That way, the tank gets it's CO2 and I got my alcohol. Getting married and having kids put an end to that dream.

Hey you can enjoy your brew and get co2 for the reactor.




CaptiveReef

[RustySnail]

What about running RO trhough a standard calcium reactor? Would not the input of CO2 to H20 (with some backpressure) cause the reactor to form "seltzer"? At the very least you are starting at a pH that is 1.2 lower than your tank water and with no alkalinity buffering (should greatly reduce the CO2 demand for acid formation; correct?

Another question is what exactly is in seltzer? If it is simply un-sweetened soda water; I would be careful. Most sodas list phosphoric acid as an ingredient. I dont think you would want anything with phosphorous going into the system. Good thought in an overall sense, I've often wondered what soda water mixed with calcium-carbonate media would do also.

[Randy Holmes-Farley]

Seltzer (soda water) is simply CO2 dissolved into fresh water. There are no other ingredients when unflavored. I recommend it for reducing pH in high pH circumstances.

What about running RO trhough a standard calcium reactor?

Very little CaCO3 will dissolve into normal RO water. If you add CO2 continually, more will dissolve, but not appreciably more than in seawater at the same low pH (probably less). It is turns out that CaCO3 is more soluble in seawater than in fresh water at the same pH.

So there is likely no advantage in using fresh water.

I discuss some related issues in this article:

Calcium Carbonate as a Supplement
http://www.advancedaquarist.com/issu...y2002/chem.htm

from it:

"Dissolution of CaCO3 in Water Prior to Addition

The best way, in my opinion, to use calcium carbonate as a supplement is to dissolve it in fresh water prior to addition. In this sense, it can be used rather like limewater. One can rig up an automatic evaporation replacement system using appropriate pumps and float switches, and just use water saturated with CaCO3 instead of limewater. Alternatively, one can simply pour the saturated water into the tank each day. Unfortunately, the fact that you can add it this way is a mixed blessing. One reason that you can add it this way is that there is so little present that the carbonate does not drive up the pH too much.

So how much goes into solution? This question is rarely addressed directly, and it is because of one big complication: carbon dioxide from the atmosphere. In the case of limewater, it is partially destroyed by atmospheric carbon dioxide (producing insoluble CaCO3 from the dissolved calcium and hydroxide). In the case of calcium carbonate, however, the solubility is actually increased by mixing with carbon dioxide. The reason that the solubility is increased is that the carbon dioxide enters the water, becomes carbonic acid (equation 1), and largely combines with carbonate ions to form two bicarbonate ions (equation 2):

The net effect is that the concentration of carbonate ions declines: since the solubility of calcium carbonate is governed by the multiplication product of the calcium and carbonate concentrations (equation 3), more calcium carbonate can dissolve to regain saturation.

Knowing the Ksp and some other constants, it is a textbook calculation to determine how much calcium carbonate can dissolve in pure water in the absence of atmospheric carbon dioxide. Pankow (Aquatic Chemistry Concepts; 1991) carries out this calculation for calcite (a slightly less soluble form of calcium carbonate than aragonite).

For those really interested in the chemical details, this calculation is actually much more complicated than it would first appear (i.e., more complicated than for a simple salt like NaCl). You cannot simply solve equation 3 for [Ca++] and [CO3--]. You need to take into account the fact that some of the carbonate that comes from dissolution will be converted into bicarbonate (HCO3-) and even carbonic acid (H2CO3). This conversion permits more CaCO3 to dissolve before the carbonate concentration rises too high to dissolve any more. One also needs to take into account the fact that calcium can exist as CaOH+, which effectively lowers the calcium concentration (though not very extensively at pH values below 11).

From this calculation, we find that the solution at equilibrium contains about 6 ppm calcium and 0.3 meq/L alkalinity, and results in a pH of 10.0. If we correct this result for aragonite instead of calcite (which is slightly more soluble), we get about 10 ppm calcium and 0.5 meq/L alkalinity, with a pH of just over 10 (which is what about what I got when I initially dissolved both AragaMIGHT and Southdown aragonite sand in RO/DI water). For comparison, full strength limewater contains about 820 ppm calcium and 41 meq/L alkalinity.

The calculation is even more involved when atmospheric carbon dioxide is allowed to enter the system. Thankfully, Pankow has again done the calculations for us. In equilibrium with normal atmospheric carbon dioxide, the solubility is increased by about a factor of 3, with the alkalinity about 1 meq/L and the calcium about 20 ppm. In this case, the pH drops to about 8.3 as the carbon dioxide enters the system. Confirming Pankow’s calculation, this result is about what I got when I let both AragaMIGHT and Southdown aragonite sand sit in RO/DI water for a few days). Still, these calcium and alkalinity values are about 40X lower than for saturated limewater, so are likely not enough to satisfy the needs of most reef tanks.

At one point I had the bright idea of adding aragonite to seltzer (soda water) bought at the grocery store to really boost the solubility and maybe have a nice, liquid additive. Seltzer has far more carbon dioxide in it than water in contact with normal air (which is why it goes flat when open), and that extra carbon dioxide will cause a great deal more calcium carbonate to dissolve (at 3.5 atmospheres CO2, the solution would contain more than 10 meq/L alkalinity and would be similar to limewater in potency, but much lower in pH). If only I had been able to mix them…… Instead, it ended up a science experiment for the kids, with the added aragonite sand providing a perfect surface for the carbon dioxide to turn into the gas phase and erupt from the bottle as a fountain of water, gas, and sand!"

[Bubafat]

What about pop rocks...you could get enough pop rocks, add water, then bubble the CO2 produced through some aragonite!

Heck, while you are at it why not just combust propane and oxygen, feed the effulent gas through a cooling line then to a Ca reactor?

[RustySnail]

Thanks for the info Randy... As always, the guys who know the science in this realm are the chemists, not all of us 'alchemists'

A dry reactor (primed with CO2) which drips seltzer across the surface of the lime might work better at controlling the rapid dissolving/bubbling....

[rcmike]

I have always wondered how it would work if you had freshwater and CO2 going into a calcium reactor and then emptying into the tank. I would think it would take much less CO2 to lower the PH enough to dissolve the media. Has anybody ever tried it?