Kalk slurry aeration

[Randy Holmes-Farley Verified Community Expert]

Here's a nice table of some indicator dyes:

pH Indicator Chart - Colors and Ranges

Get a handy pH indicator chart. See the colors and pH ranges and learn how to choose an acid-base indicator.

sciencenotes.org

 

[piranhaman00]

I came across this thread from @Lasse thread and decided to try it out for fun.

pH is typically 7.9 -8.1, skimmer pulling air from outside. 420 gallon system in basement with suspected high CO2.

Set up “bubble tower” with 48” of 2” PVC, any wider and it’s too expensive for a trial run. Drilled hole in top to run the pvc pipe in that is being pulled on by a RO skimmer pump that is just turning in sump ( loud bubble sounds). Air is being pumped in by air pump.

I originally put 50g Kalk and 10g NaOH into 1 gallon of water and mixed thoroughly and put in reactor. When I turned bubbles on the tower overflowed significantly. I had to lower the water level to only about 24”, the bubbles rise another 12”.

I put my pH probe right on the pump so I can measure the ph of the water there and stop the pump if I draw in the basic solution.

@Randy Holmes-Farley what ratio of kalk to NaOH would work?

Did @Garf bubbles rise so far? Your picture has the water level very close to the top.

 

[Randy Holmes-Farley Verified Community Expert]

The problem with mixing NaOH and Ca(OH)2 in water is the common ion effect. The hydroxide from the NaOH reduces the solubility of the calcium hydroxide. Thus hydroxide does not go up as much as hoped and calcium declines. It may still work, but perhaps not noticeably better than calcium hydroxide alone.

 

[Garf]

Did @Garf bubbles rise so far? Your picture has the water level very close to the top.

Water level used to rise a couple of inches, but the pipe diameter was 4 inches, that's quite a difference volume wise. I don't think there's any other way round either going bigger diameter, or pumping in less air, maybe even finer bubbles if they are so large they combine to form a big bubble that forces it to act like a pump, making a mess. Smaller bubble makers clog quicker.

 

[piranhaman00]

Possibly you are limited by the skimmer's capacity for gas exchange? Most skimmers happen to do a reasonable job at aeration, but this is not the intended use case and ime they are not the most effective tool for aeration.

Instead my suggestion is to use an air pump and airstone(s). An air pump will have much more airflow than a skimmer and therefore far more effective aeration. The air pump outlet would simply bubble through your cylinder filled w/kalk slurry (need a check valve or place pump above water line so slurry won't backfill into pump when powered off), and at the cylinder outlet plumb to an airstone submerged in the sump or wherever.

I use pentaire fine pore diffusers, which are significantly better than airstones but also cost more (~$30 for a 9in diffuser):

Pentair Aquatic Eco-Systems Sweetwater Fine-Pore Diffusers for Ozone and Pure Oxygen

Sweetwater fine-pore diffusers are the same high quality as our regular Sweetwater diffusers.

pentairaes.com

For an air pump, the more airflow the better. I have an "Active Aqua" Air Pump Model AAPA110L. It's old and loud but puts out over 100l/min.

Question regarding using an air pump. 100l/min is nearly 4cfm. Those diffusers max at 1cfm, do you use more than one diffuser?

 

[Lasse]

I have one idea in my mind - without any diffuser - just a tube down into the media

I visit my local IKEA shop and my cabinet for good to have things. - Testrun with calcium hydroxide in order to see if it mix or not

​

So far - works as designed. Mix very well - its a slurry and water, air and Ca(OH)2 mix well. Now will nest test phase start - connecting to the skimmer. Whats worrying me is if the contact time is long enough, i.e. is the CO2 in the incoming air transferred to CO3 in the solution and finally bound as CaCO3 fast enough. I`ll be back - I miss some tubes for the moment.

Sincerely Lasse

 

[fryman]

Question regarding using an air pump. 100l/min is nearly 4cfm. Those diffusers max at 1cfm, do you use more than one diffuser?

Actually I use 4 of them. I could pretend that was intentional, but honestly that was just how many fit nicely in my sump

BTW, this is sufficient to keep a 100gal display fully aerated. My pH still increases with light cycle but never drops below 8.2.

 

[mikst]

Possibly you are limited by the skimmer's capacity for gas exchange? Most skimmers happen to do a reasonable job at aeration, but this is not the intended use case and ime they are not the most effective tool for aeration.

Instead my suggestion is to use an air pump and airstone(s). An air pump will have much more airflow than a skimmer and therefore far more effective aeration. The air pump outlet would simply bubble through your cylinder filled w/kalk slurry (need a check valve or place pump above water line so slurry won't backfill into pump when powered off), and at the cylinder outlet plumb to an airstone submerged in the sump or wherever.

I use pentaire fine pore diffusers, which are significantly better than airstones but also cost more (~$30 for a 9in diffuser):

Pentair Aquatic Eco-Systems Sweetwater Fine-Pore Diffusers for Ozone and Pure Oxygen

Sweetwater fine-pore diffusers are the same high quality as our regular Sweetwater diffusers.

pentairaes.com

For an air pump, the more airflow the better. I have an "Active Aqua" Air Pump Model AAPA110L. It's old and loud but puts out over 100l/min.

As I read thru this thread and the (https://www.reef2reef.com/threads/pulling-air-through-saturated-kalk.580645/page-2) thread, this was my first thought, to pump air into the bottom of the solution and then plumb the air coming from the surface of the solution out of the container into an airline and thru an airstone in the sump/filter.

My tank rides around 7.8 as a high. I definitely like it higher and I don't have enough corals right now to justify dosing a ton of kalkwasser just for pH raising purposes.

I guess since this thread has stagnated a little, I'll find a big mason jar with a sealing lid, some line, airstones, and air pump and experiment this weekend!

 

[Lasse]

I guess since this thread has stagnated a little, I'll find a big mason jar with a sealing lid, some line, airstones, and air pump and experiment this weekend!

Yes - I have not got further with my ideas - please report back!

Sincerely Lasse

 

[Garf]

As I read thru this thread and the (https://www.reef2reef.com/threads/pulling-air-through-saturated-kalk.580645/page-2) thread, this was my first thought, to pump air into the bottom of the solution and then plumb the air coming from the surface of the solution out of the container into an airline and thru an airstone in the sump/filter.

My tank rides around 7.8 as a high. I definitely like it higher and I don't have enough corals right now to justify dosing a ton of kalkwasser just for pH raising purposes.

I guess since this thread has stagnated a little, I'll find a big mason jar with a sealing lid, some line, airstones, and air pump and experiment this weekend!

Since my tank has grown up a bit, I've got 2 (3) yeast bottles in operation, adding CO2 to limit the pH to 8.4ish, which is a lot less hassle than trying to get the pH up. Kalk goes in at night, bicarb 2 part during the day. Tiny skimmer is activated by my ancient pH controller which draws in the CO2;

 

[Randy Holmes-Farley Verified Community Expert]

As I read thru this thread and the (https://www.reef2reef.com/threads/pulling-air-through-saturated-kalk.580645/page-2) thread, this was my first thought, to pump air into the bottom of the solution and then plumb the air coming from the surface of the solution out of the container into an airline and thru an airstone in the sump/filter.

My tank rides around 7.8 as a high. I definitely like it higher and I don't have enough corals right now to justify dosing a ton of kalkwasser just for pH raising purposes.

I guess since this thread has stagnated a little, I'll find a big mason jar with a sealing lid, some line, airstones, and air pump and experiment this weekend!

I do not agree with the premise that an air stone aerates better than a skimmer.

 

[mikst]

I do not agree with the premise that an air stone aerates better than a skimmer.

Gross aeration quantity, understandable. Especially since air bubble size is unknown (at least to me). However, I don't have a skimmer and don't intend to get one just for aeration purposes. Also, it pretty well ensures the air going thru the air line is going to make contact with water through an airstone. Dwell time in contact with water is something else entirely as the skimmer churns the air and water together on its way up the tower VS bubbles just rising 11 inches to the surface.

 

[14 foot reef]

This is very interesting, I'm always looking to stabilize or elevate my pH.

Does anyone have better detailed pictures on how these tube aerators are designed. I have a 10' tall dual Mazzi skimmer run by a MRC 6100 pump, so I have a ton of air draw. I'd like to construct one of these and give it test drive.
Thanks for any design plans.
Happy Reefing

 

[Garf]

This is very interesting, I'm always looking to stabilize or elevate my pH.

Does anyone have better detailed pictures on how these tube aerators are designed. I have a 10' tall dual Mazzi skimmer run by a MRC 6100 pump, so I have a ton of air draw. I'd like to construct one of these and give it test drive.
Thanks for any design plans.
Happy Reefing

With a big slurry reactor I imagine the worst part will be disposing of all the calcium carbonate particles that accumulate. It wasn't too bad for me as I could just lift up the bubble lamp and tip it away, quick rinse, refill. I expect a semi-recirculating design (air pump fed primarily from previously reacted air) would be most effective, as long as damp air doesn't cause electrical issues. Feeding the reactor with already low CO2 air definitely helps out, even if from outside.

 

[mikst]

With a big slurry reactor I imagine the worst part will be disposing of all the calcium carbonate particles that accumulate. It wasn't too bad for me as I could just lift up the bubble lamp and tip it away, quick rinse, refill. I expect a semi-recirculating design (air pump fed primarily from previously reacted air) would be most effective, as long as damp air doesn't cause electrical issues. Feeding the reactor with already low CO2 air definitely helps out, even if from outside.

And then use the calcium carbonate residue in a calcium reactor!

 

[Lasse]

And then use the calcium carbonate residue in a calcium reactor!

I love recycling - waste on one side of the coin - resource on the other!

Sincerely Lasse

 

[mikst]

I haven't had a chance to tinker with aerating a CaOH solution and piping the outbound air into an airstone yet, life got in the way. But I do plan to soon!
Ultimately, I think I'll want NaOH solution to bubble my air into to scrub it, but I'm can't really figure out how large of a container I should work with for that. I'm drawing up my sump and stand plans right now and trying my best to plan. Total system water volume will be about 60 gallons.
Thanks for your time.

 

[Lasse]

You should use CaOH because you want Ca to react (in water) with CO2 and form CaCO3

Sincerely Lasse

 

[mikst]

You should use CaOH because you want Ca to react (in water) with CO2 and form CaCO3

Sincerely Lasse

Thank you for answering, but, my understanding was from a materials standpoint, NaOH is more potent and would be more effective at scrubbing co2.

Also, when I said above something about taking the caco3 and putting it in a calcium reactor I was not intending to actually do that as I don't want to run a calcium react and I'm not sure what I would do with all the calcium carbonate. Sprinkle in the sump in the crypt? I'd hate to waste.

I have a water filter housing I was intending to use for this scrubber purpose. Just curious if it's big enough to perhaps not have to fill weekly for a 60 gallons of water system.

 

[Garf]

Thank you for answering, but, my understanding was from a materials standpoint, NaOH is more potent and would be more effective at scrubbing co2.

Also, when I said above something about taking the caco3 and putting it in a calcium reactor I was not intending to actually do that as I don't want to run a calcium react and I'm not sure what I would do with all the calcium carbonate. Sprinkle in the sump in the crypt? I'd hate to waste.

I have a water filter housing I was intending to use for this scrubber purpose. Just curious if it's big enough to perhaps not have to fill weekly for a 60 gallons of water system.

By the time you've sorted this out, pH shouldn't be an issue. This tank is about 4 years now. Thanks dry rock.