Kalk slurry aeration

phxreefer · Sep 8, 2022

I have made a similar reactor and am trying to dial it’s efficiency. I’m hovering around 7.9-8ph which isn’t what I was intending on hitting.
the reactor circulates the gas from the top of the chamber through a skimmer pump to mist the gas, some fresh is drawn in the balance out the vacuum created But mostly recirculated.
the gas is then drawn and fed into a secondary skimmer being used for gas exchange only no skimmate.
any ideas? I’m thinking the temps in garage may be effecting saturation of kalk? Or maybe not a large enough skimmer to exchange?

Garf · Sep 8, 2022

phxreefer said:
I have made a similar reactor and am trying to dial it’s efficiency. I’m hovering around 7.9-8ph which isn’t what I was intending on hitting.
the reactor circulates the gas from the top of the chamber through a skimmer pump to mist the gas, some fresh is drawn in the balance out the vacuum created But mostly recirculated.
the gas is then drawn and fed into a secondary skimmer being used for gas exchange only no skimmate.
any ideas? I’m thinking the temps in garage may be effecting saturation of kalk? Or maybe not a large enough skimmer to exchange?

If I'm understanding correctly, this is just saturated kalkwasser, no slurry? If so, I'm seem to remember Randy did an experiment where it depleted really fast, an hour or two or something really short anyhow.

phxreefer · Sep 8, 2022

Theres like a whole bottle of kalk in the 8 gal of water, the pump is recirculating a milky solution and mixing with recirculated gas. (Which I’m hoping would prolong the solution) A ph probe calibrated to 10&12.4 at equal temp is reading the solutions saturation
is there a difference in what youre doing?

Garf · Sep 8, 2022

phxreefer said:
Theres like a whole bottle of kalk in the 8 gal of water, the pump is recirculating a milky solution and mixing with recirculated gas. (Which I’m hoping would prolong the solution) A ph probe calibrated to 10&12.4 at equal temp is reading the solutions saturation
is there a difference in what youre doing?

How big is your tank and how long you had the bubbler running and has pH increased at all? Mine isn't going to a skimmer, just a needlewheel which is churning over 30% of the sump.

phxreefer · Sep 8, 2022

Garf said:
How big is your tank and how long you had the bubbler running and has pH increased at all? Mine isn't going to a skimmer, just a needlewheel which is churning over 30% of the sump.

Only 30g w sump, have been working on this for a week or so, determined to get highest ph possible before dosing, I think you’re idea is good. Been following along and doing research this whole time. Trying to dial it in. My ph has increased minimally .1 overall, I have noticed much less fluctuation in day/night ph
I’ll flush the reactor and refill, ph is still reading 12.4 tho
this Is the skimmer I First used for gas exchange controlled by apex ph monitor. (Which I haven’t used yet because ph isn’t high obv.) Nothing fancy but fed by a good needlewheel. I since upgraded to the larger version of same skimmer

you can see a revised attempt at your coke bottle in the photo too, I as well concluded not enough exposure and built the 6’ reactor as proof of concept

Garf · Sep 8, 2022

phxreefer said:
Only 30g w sump, have been working on this for a week or so, determined to get highest ph possible before dosing, I think you’re idea is good. Been following along and doing research this whole time. Trying to dial it in. My ph has increased minimally .1 overall, I have noticed much less fluctuation in day/night ph
I’ll flush the reactor and refill, ph is still reading 12.4 tho
this Is the skimmer I First used for gas exchange controlled by apex ph monitor. (Which I haven’t used yet because ph isn’t high obv.) Nothing fancy but fed by a good needlewheel. I since upgraded to the larger version of same skimmer

you can see a revised attempt at your coke bottle in the photo too, I as well concluded not enough exposure and built the 6’ reactor as proof of concept

For what it's worth my pH was already reading 8.25 to 8.3 in the day, so 0.15 to 0.2 increase (I do replace Alk with saturated kalk) 60% at night.

fryman · Sep 8, 2022

phxreefer said:
I have made a similar reactor and am trying to dial it’s efficiency. I’m hovering around 7.9-8ph which isn’t what I was intending on hitting.
the reactor circulates the gas from the top of the chamber through a skimmer pump to mist the gas, some fresh is drawn in the balance out the vacuum created But mostly recirculated.
the gas is then drawn and fed into a secondary skimmer being used for gas exchange only no skimmate.
any ideas? I’m thinking the temps in garage may be effecting saturation of kalk? Or maybe not a large enough skimmer to exchange?

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.

phxreefer · Sep 8, 2022

fryman said:
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.

ill give it a shot, that was my original idea And much more simple, however I’d like to rely on efficiency Of micro bubbles and fluid exposure time over pure pump aeration volume. (I think my sump would have to be one huge foam skimmer, and on only a 30g Tank that’s ridiculous, impossible on a 200 which I’m testing This theory for) I wanted to recirculate gas with the Nielsen style reactor to give best exposure with micro bubbles being recirculated through the slurry. And also recirculate skimmer cap gas back into the system. Pretty much a closed loop with small amount of fresh outside air used to balance vacuum pressure in reactor

I was under the impression a skimmer would do a better job exposing water to air, as the bubbles are so fine, contained, and as they swirl and are suspended in the skimmer, having more contact time rather then Just rising to surface and being released to atmosphere. by increasing the skimmer & pump size I was hoping to notice a difference, I did not.
So I’ve either exhausted all co2, the slurry is not scrubbing- either moving to pickling lime for higher ph, dosing vinegar, the temp is too high and solution isn’t efficient) or the skimmer isn’t exposing the scrubbed gas to the tank water enough. I have noticed changes, just not enough.

it is good to know that you’re only seeing a .15 ish max increase

i am also running a week of co2 media in a reactor to scrub the outside air and compare findings.
i have also put a top on the tank itself and reduced surface agitation to see if I can get most of the gas exposure of the tank through this scrubbed gas, so I’m not combatting my inside air

when out of town the tank sat easily and steady at 8.1-8.3 with no dose. Me and my stupid breathing family are screwing me.
The in. And out, in and out, over. And over...

Garf · Sep 10, 2022

Now that I can keep it up all night I’m trying to get the daytime rise down. To this end I’ve changed from Kalk in the day to bicarbonate (helped a bit), and added a fresh air line to the lid, connected to a little air pump which operates during photosynthesis on a timer. I’ve thrown another 100 grammes of lime in the tube so it doesn’t deplete over the next few days, simple.

Garf · Sep 11, 2022

I need to reassess this strategy,lol. Although applying fresh air combined with bicarbonate stopped the pH increase in its tracks, it’s increased and transferred the swing to a lower pH overall. The pH was 8.38 when I turned the fresh air on, where it stayed for 8 hrs, not moving at all. This morning it is 8.17, very odd. Now reducing the time the fresh air is pumped to 3 or 4 hrs in peak photosynthesis, see what happens.

Edit - yesterday I also moved the location of my dosing lines (made a DIY pipe holder from an old algae magnet) but can’t see how that’s got anything to do with it. Hey ho, onwards and upwards.

Edit 2 - scratch that, bubble ring was clogged up. That’s another 5 minutes I’ll never get back. Let’s try again

Garf · Oct 9, 2022

Wife did a fantastic job at camouflage, you can hardly tell the thing is there now

Randy Holmes-Farley · Oct 10, 2022

In three years, you won’t see it at all after it grows. lol

Garf · Dec 10, 2022

Update - my kalk consumption has increased from 680mls day (approx 0.4DKH) to 1400mls day (approx 0.8DKH) since starting this test. I assumed this increase in kalk consumption would off set the winter closed door / CO2 thing. Well, today I hit a low of 7.95 (it normally drops a little on weekends when we are not at work). Presumably that would have been 7.8 to 7.85 without my bubbly thing, perhaps even lower if in fact I increased calcification by increasing pH over the last few months, therefore increasing kalk additions.

Garf · Dec 11, 2022

Turns out my kalk doser has packed up again, lol. So, emergency manual drippy thing in operation for now.

Saltyanimals · Feb 9, 2023

Garf said:
Turns out my kalk doser has packed up again, lol. So, emergency manual drippy thing in operation for now.

Are you still running the experiment kalk bubble thingamabob ? =) Curious on what you ultimately settled on for final design if it's still working for you.

Garf · Feb 9, 2023

Saltyanimals said:
Are you still running the experiment kalk bubble thingamabob ? =) Curious on what you ultimately settled on for final design if it's still working for you.

Yep still using it. Only thing I've changed is putting a flexible 2 inches of airline on the air going into the kalk, which makes it really easy to clean when it clogs up, roughly weekly.

Doctorgori · Jul 29, 2023

@Garf any chance you got Apex graphs, charts , whatever…. so we might be able put actual metrics on that thing for sorta a actual cost/ benefit analysis (cheapo pickling lime vs. “Lab grade media”)
——-

Garf · Jul 29, 2023

Doctorgori said:
@Garf any chance you got Apex graphs, charts , whatever…. so we might be able put actual metrics on that thing for sorta a actual cost/ benefit analysis (cheapo pickling lime vs. “Lab grade media”)
——-

Nah, no Apex. Tank is doing well though and this bubbly thing has cost £12 for the year in hydrated lime. PH ranges between 8.3 and 8.5 when the pH controller triggers an air pump to add untreated room air. Currently adding 1700mls a day of Kalk for alkalinity, split into 12 doses.

taricha · Jul 31, 2023

Wanted to comment @Garf that I messed around with this for no reason (tank next to window anyway).
I wanted to know if pH indicator color in the slurry reactor can work to tell you if your media is exhausted.
It seems it does work. I added API high range pH indicator to a bottle of water with a little NaOH + Ca(OH)2 and just put an airline in it to bubble.
The color eventually shifts from max pH purple (right) to something with more red/brown/grey (left).

This isn't a leading indicator - it probably stopped helping with pH long before you see a color change, but it does tell you that CO2 is rising in the slurry media just by looking, no meter required.