Neptune Aquatics

Pressurized kalk reactor

Patio said:
Vigorous mixing seems like a solvable problem but like you mention there are other ways to consistent alk delivery.


Did you give it another shot after correcting stirring duration?
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My original post have some typo due to autocorrect. Fixed that. I meant i mess with the stirring duration but it didn't make much of a different. IN my setup, i use a mag stirrer. Run it from 8mins to 20mins. I can clearly see the the entire container get cloudy when the mag stirrer turn on. I have full control when and how long to run the mag stirrer. 20mins seems a lot. Is it?
Patio said:
Does this mean vigorously stirring is not the problem?

Sorry for all the thinking out loud.lol I can't wrap my head around not having a solution for keeping saturation.
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I cannot say for sure stirring vigorously is the problem or the solution. Like i said, if i add fresh kalk powder, same stirring duration, the potency is back to normal.

Just to repeat. The problem i observed :

1. Potency drop over time (4 days in my case)
2. Stirring vigorously on 3rd day did not help. To be specific, i stir in the morning, let it settle and dose at night. I can try stirring close to night time and have less settle time to see if that helps.
3. Adding more kalk help. Per my calculation , for the volume i'm dosing , max saturation is 2.5tablespoon of kalk per week. I added 5 tablespoon and potency drop after 4 days.


I cannot understand the logic either. The mixing container is 6x6inch, water fill up to 2" to the top. Container is not airtight, but have a lid. We are talking about 72cubic inch of airspace at the top. Water volume is ~3+ liters.
 
I'm seriously thinking of abandoning Kalk and strictly go with 2 parts. Kalk alone cannot meet my system demand, so i'm dosing 2 parts in addition. The advantage is simplicity ie less thing to maintain. The cons is PH drop ( which is the main reason i added Kalk).

Who cares about PH, right? Open window doesn't help much. In a different thread, it could be my skimmer is underpower, which could be one of the reason.
 
would doubling from 5 tbs to 10 tbs make a difference? since you said adding more restored potency. or is the kalk losing potency by being in solution?
 
psidriven said:
would doubling from 5 tbs to 10 tbs make a difference? since you said adding more restored potency. or is the kalk losing potency by being in solution?
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I meant the following . If I add fresh kalk , the potency restore for 4 days. I doubt starting with 10tbs vs 5 tbs make much difference since I’m dosing equivalent of less than 2 tbs .

It sure seems like kalk losing potency in the solution.

My setup is unique. Fill and drain ( dose to tank) daily. Stir 20mins after fill, let the solution rest for 8 hours before dosing at night.
 
RandyC said:
Carbon dioxide is what is causing the pH if you kalk solution to fall. You can explore adding vinegar to your kalk.

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I am aware of adding vinegar to the kalk solution. However I also read it’s a form of carbon dosing . My nutrient is hovering at zero, any form of carbon dosing may complicate things. Trying to balance over feeding , dosing nitrate and phosphate to keep above zero.
 
Experiment with slow but longer duration stirring help. I set the stirrer to 50% power, and let it stir for 1 hour. The ‘crust’ at the top of the solution did not get disturbed during the process. I assume you this is good as it prevent co2 from entering.
 
As I understand it, the main problem kalk stirrers struggle with are the opposing issues of:

1. Kalk-saturated water is heavier than fresh water, and the more saturated the more heavy. So it naturally sinks, away from the outflow tube.
2. You can fully saturate kalk water pretty easily but it requires vigorous stirring. Once saturated, it will stay saturated without stirring as long as you don’t add more water.
3. By definition the contraption is frequently adding new fresh water than needs to be stirred to be saturated, or else will float to the top.
4. Stirring repeatedly enough to saturate causes too much CO2 exchange which gradually precipitates out the kalk as calcium carbonate, which cannot go back into solution.

So basically the chemistry is working against you. Making up a large batch and stirring well once gets around all these issues but has the huge drawback of requiring a large container. Add to this the physical issues of kalk being hard on pump impellers and other moving parts.
 
Good news is the general idea was successful!

Continuing to ideate on contraptions to make these better, it seems like the views are:

A. Doing a big mix gets things where people want
B. Mix being stable stays stable
C. Kalk stirrers have a compromise of needing to mix, but also let it stabilize so you can be confident you get a consistent quantity added per mL you add

I wonder if the way to connect both these would be a container with two sections. One section is the stable mix you use for the tank, one is the mixing section. Probably unfortunately requires another pump...

Water goes into the mixing section. Fills until hits a float. Vigorous mixing begins. Use a paddle so you can have a ton of Kalk powder in it. Mixing ends, fluid rests.

Then pump from that reservoir into the other, slowly. Slowly because you're trying to keep the crust on the second reservoir.

That second reservoir is pumped from normally to add to the tank. It's being filled from a vigorous mix which should be at a high and consistent potency. The second reservoir is never stirred, and only added from the first, so it should also always be potent.

Because there's two separate reservoirs, you don't have to synchronize the adding to the tank with the mixing. On a schedule, or based on float valves, do the mixing and then the adding.

Additionally because this would be controlled, you could size both reservoirs to be approximately one day's use if desired.

Finally, unlike the previous idea of the two pumps and timings, this one should be able to use the absolute cheapest peristaltic pumps out there.

Shouldn't that work and avoid the gotchas?

If built from scratch, I think: $5 pump for filling mixing reservoir. $5 pump for moving water from mixing to dosing reservoir. Slightly nicer for dosing. $5 worth of float valves. $8 controller hardware. I think high torque pumps for mixing are $10ish (worm gear) but I'm not sure they'd spin fast enough. 2 reservoirs. Some sort of paddle, maybe 3d print. A couple connections. Some DC power supply.
I'm quite confident that could be built in an afternoon with some AliExpress parts.
 
The idea works but a bit more hardware and real estate with second reservoir. Since I figure I can stir slowly without disturbing the crust, I can stir for a long time , hopefully without impact on potency. I’ll report back in a week if this works long term.

I’m not worried about overfilling with all the fail safe I have. I’m not filling and dosing at the same time like any commercial kalk stirrer. I’m only filling once & stir in the morning , rest then dose throughout the night. Repeat the next day.

I don’t fill to the float sensor either. Fill to 10ml less everyday. Once a few weeks, I’ll manually top off.
 
@richiev another idea I was thinking about is a kalk powder dispenser, using an auger style drum like the Avast Plank feeder. This would eliminate the second container.
1. Kalk is dispensed into the reservoir
2. Fresh water is filled and mixed with motor driven paddle
3. Kalk is then dispensed until the reservoir is empty, then repeat

Would need sensors to determine when the reservoir is full and empty. This may be a problem since kalk can foul up typical optical sensors and mechanical float switches.
 
CaseyP said:
@richiev another idea I was thinking about is a kalk powder dispenser, using an auger style drum like the Avast Plank feeder. This would eliminate the second container.
1. Kalk is dispensed into the reservoir
2. Fresh water is filled and mixed with motor driven paddle
3. Kalk is then dispensed until the reservoir is empty, then repeat

Would need sensors to determine when the reservoir is full and empty. This may be a problem since kalk can foul up typical optical sensors and mechanical float switches.
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Let's pretend kalk solution is fully saturated at 5g of Kalk in 1L of water. It's fully dissolved and couldn't take any more.

What's the difference between:

A. Put 10g of kalk in 1L of water, mixinn, draining all the water out over time, then adding another 1L of water and mixing the rest
B. Adding 5g of kalk to 1L, then another 5g to the next 1L

In both cases you theoretically are saturating.

I've thought about trying to add powder, but never thought of how to do it. The auger approach seems interesting if you can keep the kalk powder reservoir dry and air tight to avoid it losing potency from air.

The auger add approach is effectively B in my above example. Adding water and mixing is effectively A. I don't understand the chemistry enough to know if/why B has different effects than A.
 
Functionally no difference. I'm thinking form factor since the selling point for a kalk reactor is space savings. Most setups I see the kalk stirrer under the stand. In my head I'm imagining the reservoir at the bottom and the kalk hopper, peristaltic pumps, and mixing motor all in an housing sitting on top.
 
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I didn’t read thru the whole thread. I’ll tell you what I know about Kalk stirs as I’ve been using one for ever and a day. I’ve been using the same Kalk stir for 20 years on and off. Gray sea aquatics is advast before advast. That’s how long I’ve been using it. And ways. Here’s what I learned. The motor is a clock motor. I’ve changed them before. Super easy. You can get different speeds if you like. I glued a mesh on my stir shaft at the bottom so it fluffs up the Kalk. I extended the intake tube almost to the bottom so in coming water is mixed directly into the Kalk. There is a skin on top of the water. This forms a seal. Don’t disturb it. So too much mixing is not good. I dose almost 2 gallons at night. 6 tablespoons every 7 days. If it’s running out. The Kalk will start to float up in the water column because of the paddles on the stir at the bottom. Since I dose at night. I add Kalk during the morning so it will settle. I dose in a high flow area at the beginning of my sump. So it get mixed faster. Oh. All Kalk isn’t the same. Some are better than others.
That’s all that comes to mind. Hope it helps.
 
I’ve been using the same Kalk for a few years. I bought a 50lbs of Mississippi lime. So I’ve been using that for years. But I remember about 10 years ago. I tried Kent ? Or brightwell. It was better. Like the ph was more potent in the mix.
 
newfly said:
The idea works but a bit more hardware and real estate with second reservoir. Since I figure I can stir slowly without disturbing the crust, I can stir for a long time , hopefully without impact on potency. I’ll report back in a week if this works long term.

I’m not worried about overfilling with all the fail safe I have. I’m not filling and dosing at the same time like any commercial kalk stirrer. I’m only filling once & stir in the morning , rest then dose throughout the night. Repeat the next day.

I don’t fill to the float sensor either. Fill to 10ml less everyday. Once a few weeks, I’ll manually top off.
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For the avast -it slowly mixes the water 24/7 at a very slow pace. However -as others have mentioned -it forms a crust at the top and unless I mess it with it or add new powder every two weeks -it stays as is.
I measured it Friday after 14 days (or rather on day 14) and the PH was still 12.

So if you can get the mag stirrer to run for long periods of time and not disrupt the crust -hopefully it does not lose potency after 4 days.

One thing to note- you had mentioned that you use BRS kalk -avast advises against using it in their stirrer as it is “clumpy” and doesn’t mix as well and can burn out the motor. As you are attempting the same strategy to some degree -perhaps a change in brand might help. I use captive8 and it works well.

Hope you can nail it down and get to work as desired
 
Testing the pH difference between a bucket of freshly mixed saturated kalk (12.4 pH) and my avast kalk stirrer (11 pH). The stirrer still has a lot of kalk at the bottom which makes it very deceiving regarding its potency.

Already a 0.2 difference and that's at 75% of the dosing volume of the stirrer. I'm about ready to ditch the stirrer and figure a way to route a line outside so I can store a 55 gallon drum of saturated kalk.

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