Kalkwasser saturation mixing time experiment

[Boehmtown]

That’s what I always did.

So in a kalk stirrer..... There's tons of powder left in the bottom. Will it keep running close to saturation till it's all gone. or is a large chink of that calcium carbonate. And how do I tell ?

 

[rishma]

So in a kalk stirrer..... There's tons of powder left in the bottom. Will it keep running close to saturation till it's all gone. or is a large chink of that calcium carbonate. And how do I tell ?

I don’t think it will ever completely dissolve because there’s going to be some calcium carbonate and impurities. I’d just add some excess periodically so there is plenty in there.

Many years ago I made a kalk stirrer based on a Nielsen reactor design. I found it didn’t really dose saturated kalk and was not very consistent, perhaps because my dosing rate/reactor size/mixing time combination didn’t allow for it. It was fine but didn’t meet my needs for consistency of alkalinity and required maintenance so I moved to a large reservoir which was simple, consistent, and predictable.

 

[Boehmtown]

I don’t think it will ever completely dissolve because there’s going to be some calcium carbonate and impurities. I’d just add some excess periodically so there is plenty in there.

Many years ago I made a kalk stirrer based on a Nielsen reactor design. I found it didn’t really dose saturated kalk and was not very consistent, perhaps because my dosing rate/reactor size/mixing time combination didn’t allow for it. It was fine but didn’t meet my needs for consistency of alkalinity and required maintenance so I moved to a large reservoir which was simple, consistent, and predictable.

I mix 24/7 and I noticed even with that and having inches of kalk in the bottom. If I add fresh, it bumps my alk up. I'm unsure if there's just a level of over saturated kalk that goes in right after it's added that does it, or is it really upping the saturation. I plan to clean it out today and add small amounts weekly , at some point stop cause it's an inch or two in there and see what happens and how long I notice it stays potent.

 

[rishma]

I mix 24/7 and I noticed even with that and having inches of kalk in the bottom. If I add fresh, it bumps my alk up. I'm unsure if there's just a level of over saturated kalk that goes in right after it's added that does it, or is it really upping the saturation. I plan to clean it out today and add small amounts weekly , at some point stop cause it's an inch or two in there and see what happens and how long I notice it stays potent.

I think it’s possible that the very fine particles in a fresh scoop dissolve quickly and do a better job of saturating. In theory, these reactors should provide saturated kalkwasser but in practice I’m not convinced they do.

 

[Boehmtown]

I think it’s possible that the very fine particles in a fresh scoop dissolve quickly and do a better job of saturating. In theory, these reactors should provide saturated kalkwasser but in practice I’m not convinced they do.

I'm still new to kalk stirrers. So I am starting fresh again today. But at first, to get used to it. I was just adding a very small initial amount and added in once a week what I used before with saturated kalk and it was working more consistently. I dumped a bunch in for vacation and was waiting for at least half to go away before I started adding again. And I just lost potency after a couple months, in my non scientific, non accurately measured opinion

 

[bubbgee]

I'm still new to kalk stirrers. So I am starting fresh again today. But at first, to get used to it. I was just adding a very small initial amount and added in once a week what I used before with saturated kalk and it was working more consistently. I dumped a bunch in for vacation and was waiting for at least half to go away before I started adding again. And I just lost potency after a couple months, in my non scientific, non accurately measured opinion

I add a tsp kalk once there’s a dip in alkalinity. During summer, I would add one every day as the evaporation rate is higher. Now I am trying to figure out how much frequent I need to add as the evaporation is lower.

 

[rishma]

I add a tsp kalk once there’s a dip in alkalinity. During summer, I would add one every day as the evaporation rate is higher. Now I am trying to figure out how much frequent I need to add as the evaporation is lower.

This is why I eventually separated my ATO from my kalk doing. I mix it saturated and then dose a volume I want for a specific alkalinity. It’s easier than trying to guess the right amount of powder. But I’m also more precise than is really necessary.

 

[Randy Holmes-Farley]

So in a kalk stirrer..... There's tons of powder left in the bottom. Will it keep running close to saturation till it's all gone. or is a large chink of that calcium carbonate. And how do I tell ?

Such reactors often surprise people by producing below saturation potency.

 

[rishma]

Update: I measured conductivity after 24 hours and it went up slightly. About 99.7% saturation.

 

[KJoFan]

40 minutes eh? I guess my method of dumping some kalk into the container, filling it with RO/DI and shaking it 3-4 times isn't quite adequate.

 

[rishma]

40 minutes eh? I guess my method of dumping some kalk into the container, filling it with RO/DI and shaking it 3-4 times isn't quite adequate.

Well, I’m not so sure. I think if you are consistent that’s might be good enough.

I know in the old days I would do that in a jug and drip it overnight from an IV dripper. I thought I was pretty sophisticated.

 

[EnterName]

Update: I measured conductivity after 24 hours and it went up slightly. About 99.7% saturation.

I know you are using a really good conductivity meter, but do you think 0.3% is within the margin of error due to temperature, impurities, etc.?

Just curious: How do you clean the electrode after it has been sitting in Kalkwasser? Dilute HCl? Acetic acid?

 

[rishma]

I know you are using a really good conductivity meter, but do you think 0.3% is within the margin of error due to temperature, impurities, etc.?

Just curious: How do you clean the electrode after it has been sitting in Kalkwasser? Dilute HCl? Acetic acid?

Fair questions.

I just rinsed it in RODI water. It’s shiny black and looked clean. It’s not a typical glass bulb type electrode. Clean enough? I’m not certain.

Could be margin of error, though this thing is pretty precise. Temperature was 20.2C so very close to the experiment temp.

Did it actually increase in potency? Not sure but I am pretty confident it didn’t go down.

 

[KJoFan]

Well, I’m not so sure. I think if you are consistent that’s might be good enough.

I know in the old days I would do that in a jug and drip it overnight from an IV dripper. I thought I was pretty sophisticated.

My method matches my level of effort overall probably, but I will keep this 40 min figure in mind, just in case I want to up my game.

 

[Randy Holmes-Farley]

I never even tried to attain 100%. I stirred my Brute cans to about 8+ mS/cm and stopped.

 

[ChrisfromBrick]

this is good information. I’m going to start to do this with a power head for 40 min with 5g bucket with lid.

I’d like to get a more attractive kalk reservoir other than a bucket or jug. Something very tall but small footprint.

Thanks!

 

[rishma]

I never even tried to attain 100%. I stirred my Brute cans to about 8+ mS/cm and stopped.

But just think of the dozens of dollars you could have saved over the years by mixing full strength

 

[rishma]

I am now wondering if passive dissolution after just 10 minutes of mixing might achieve full saturation. That experiment will have to wait until current reservoir is empty. But longer mixing surely doesn’t hurt anything.

 

[Randy Holmes-Farley]

I am now wondering if passive dissolution after just 10 minutes of mixing might achieve full saturation. That experiment will have to wait until current reservoir is empty. But longer mixing surely doesn’t hurt anything.

My water was very cloudy when I stopped stirring and I’m sure there was some additional dissolution while the fine particles slowly settled out.

 

[IPT]

This is why I eventually separated my ATO from my kalk doing. I mix it saturated and then dose a volume I want for a specific alkalinity. It’s easier than trying to guess the right amount of powder. But I’m also more precise than is really necessary.

I do the same. First off I don't have to worry about kalk dosing volumes changing based on evaporation rates, but also, I did have an ATO pump fail once (on) and it was a disaster.