Kalkwasser not mixing to 10.3 ms?

[arking_mark]

@Randy Holmes-Farley

So I got an Apera EC20 Conductivity Meter to measure my Kalkwasser potency. I'm assuming the meter is good enough for that purpose as it reads 0-20ms. However, my freshly mixed Kalkwasser is only getting to 7.13ms and not the expected 10.3ms. Am I missing some secret mixing technique that gets it to saturate? It's being mixed in 2gal IceCap magnetic stirrer reactor...the one that is always cloudy

 

[Randy Holmes-Farley]

Try putting 2 tablespoons of the calcium hydroxide in a cup of RO/DI water at room temperature, stir a few minutes and see what you get.

it could be the meter is off, or the stirrer is not producing saturated limewater.

 

[arking_mark]

Try putting 2 tablespoons of the calcium hydroxide in a cup of RO/DI water at room temperature, stir a few minutes and see what you get.

it could be the meter is off, or the stirrer is not producing saturated limewater.

So I re-calibrated the meter and it tests perfectly against the two reference solutions 1423us and 12.88ms. The 2 tablespoons of Kalk in 8oz of water only gets to 8.6ms. Am I still missing something? Could BRS Pharma Kalk not great?

 

[Randy Holmes-Farley]

So I re-calibrated the meter and it tests perfectly against the two reference solutions 1423us and 12.88ms. The 2 tablespoons of Kalk in 8oz of water only gets to 8.6ms. Am I still missing something? Could BRS Pharma Kalk not great?

Might need more mixing, might be some other sort of error. Water isn't warm, right?

Does that meter automatically adjust for temperature?

Where did the reference solutions come from?

 

[arking_mark]

Might need more mixing, might be some other sort of error. Water isn't warm, right?

Does that meter automatically adjust for temperature?

Where did the reference solutions come from?

Mater isn't warm about 73.

The meter automatically adjusts for temp.

Reference solutions come with the meter...

 

[arking_mark]

Mater isn't warm about 73.

The meter automatically adjusts for temp.

Reference solutions come with the meter...

One more thing to note is that the 2 tablespoon of kalk with 8oz of RODI has a ton of kalk that seetles on the bottom...I've mixed it several times. I feel confident the EC meter (which is new and I re-calibrated).

 

[Hermie]

Somewhat related...

In a sealed container with maybe 10% volume of air vs 90% volume kalk solution (rodi + kalk to theoretical saturation levels), is it okay to violently shake the container so as to completely mix the kalk and the water? I'm always worried about introducing too many microbubbles into the solution, producing unwanted precipitates, but if the volume of air is relatively small, there can't be "that" much CO2 in the container, right? As a rule of thumb is it better to vigorously shake a kalk solution to ensure complete mixing than to be gentle and allow for unmixed kalk to settle in the container... ?

 

[Randy Holmes-Farley]

One more thing to note is that the 2 tablespoon of kalk with 8oz of RODI has a ton of kalk that seetles on the bottom...I've mixed it several times. I feel confident the EC meter (which is new and I re-calibrated).

It should have lots of excess. That's the point: saturate with plenty to spare.

 

[arking_mark]

It should have lots of excess. That's the point: saturate with plenty to spare.

So I contend that 8.6ms is what the EC meter reads...I'll try my GHL....since it is mixed in the a cup that I can easily bring to the meter.

 

[Randy Holmes-Farley]

Shaking and mixing with the same air is fine. It is bubbling in fresh air constantly that will deplete it.

Whatever the reason, if conductivity goes no higher, use this as saturated, and then compare to the reactor effluent. Potency is linear with conductivity. So stirrer at 7.13 and saturated at 8.6 mS/cm means the reactor is producing 7.13/8.6 x 100 = ~83% saturated limewater (kalkwasser).

 

[arking_mark]

Shaking and mixing with the same air is fine. It is bubbling in fresh air constantly that will deplete it.

Whatever the reason, if conductivity goes no higher, use this as saturated, and then compare to the reactor effluent. Potency is linear with conductivity. So stirrer at 7.13 and saturated at 8.6 mS/cm means the reactor is producing 7.13/8.6 x 100 = ~83% saturated limewater (kalkwasser).

So the GHL measures 9.4ms and the EC Meter read 8.6ms. I'll use your advice for potency then...not sure why the meter would measure low. It tested perfect against reference solutions.

 

[Mono]

@Randy Holmes-Farley

So I got an Apera EC20 Conductivity Meter to measure my Kalkwasser potency. I'm assuming the meter is good enough for that purpose as it reads 0-20ms. However, my freshly mixed Kalkwasser is only getting to 7.13ms and not the expected 10.3ms. Am I missing some secret mixing technique that gets it to saturate? It's being mixed in 2gal IceCap magnetic stirrer reactor...the one that is always cloudy

I know this is a somewhat older thread, but I have the exact same issue. I'm using the Orion A322 with a 4 probe conductor and temperature correction. It reads my Randy's recipe conductivity probe reference solution at 53ms so it seems to be pretty spot on.

However, my Kalkwasser usually reads around 7.0ms (give or take) at room temperature. Even when I mix in extra Kalk into my RODI it doesn't seem to go up.

I wonder if anyone ever hits 10.3ms? Or if there is some trick to mixing?

Or should I just go with an over-saturated calibration solution, get a reading and just take it from there?

 

[arking_mark]

I know this is a somewhat older thread, but I have the exact same issue. I'm using the Orion A322 with a 4 probe conductor and temperature correction. It reads my Randy's recipe conductivity probe reference solution at 53ms so it seems to be pretty spot on.

However, my Kalkwasser usually reads around 7.0ms (give or take) at room temperature. Even when I mix in extra Kalk into my RODI it doesn't seem to go up.

I wonder if anyone ever hits 10.3ms? Or if there is some trick to mixing?

Or should I just go with an over-saturated calibration solution, get a reading and just take it from there?

That's what I'm doing. I take a reading at saturation. That's my high...and all other kalkwasser readings are compared to that. I then top off my kalk stirrer when that reading drops off that high reading.

 

[Randy Holmes-Farley]

I know this is a somewhat older thread, but I have the exact same issue. I'm using the Orion A322 with a 4 probe conductor and temperature correction. It reads my Randy's recipe conductivity probe reference solution at 53ms so it seems to be pretty spot on.

However, my Kalkwasser usually reads around 7.0ms (give or take) at room temperature. Even when I mix in extra Kalk into my RODI it doesn't seem to go up.

I wonder if anyone ever hits 10.3ms? Or if there is some trick to mixing?

Or should I just go with an over-saturated calibration solution, get a reading and just take it from there?

I got about 10 mS/cm, but I'd go with an hugely oversaturated solution as a real 10.3 mS/cm, and also assume it is saturated.

http://reefkeeping.com/issues/2005-01/rhf/index.htm

Figure 5. Conductivity as a function of time over 10 days in an open 1-gallon
container of limewater with excess solid lime on the bottom

 

[Mono]

I guess lime is cheap enough.

I'll make an oversaturated solution and get a reading and if it works I'll overdose my Brute.

Seems like Kalkwasser is having a comeback now if it ever went away.

Thanks

 

[DeputyDog95]

Do you think I could use my Hanna conductivity meter I use for salinity to measure Kalkwasser as well?

I tried it, came up with .6ppt which is 1.21 mS/cm. Seems really low for 3 inches of Kalk sitting in a 2 Little Fishes reactor...

The Hanna device has a range of 0-40ppt if I'm not mistaken, but not sure how it would read in this solution. Thoughts?

 

[Randy Holmes-Farley]

Do you think I could use my Hanna conductivity meter I use for salinity to measure Kalkwasser as well?

I tried it, came up with .6ppt which is 1.21 mS/cm. Seems really low for 3 inches of Kalk sitting in a 2 Little Fishes reactor...

The Hanna device has a range of 0-40ppt if I'm not mistaken, but not sure how it would read in this solution. Thoughts?

Make a truly saturated solution using, say, 2 tablespoons calcium hhyroxide in a cup of Ro/DI, stir well, and read the conductivity. That's where your meter reads saturation. Lower levels are less than saturated.

There will be a lot of uncertainty, however, given the range of allowed variation in the meter response according to hanna.

 

[DeputyDog95]

Make a truly saturated solution using, say, 2 tablespoons calcium hhyroxide in a cup of Ro/DI, stir well, and read the conductivity. That's where your meter reads saturation. Lower levels are less than saturated.

There will be a lot of uncertainty, however, given the range of allowed variation in the meter response according to hanna.

That's a good idea!