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Discussion Starter · #1 ·
found some potassium test kit from lamotte. The price around a hundred dollar canadian.

Some pricey, don’t you think?
 

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Discussion Starter · #4 ·
Thanks...

Yeah, I will order one when I get some extra cash:icon_roll

Here, in Canada, Big Als is not allowed to sale this, some kind of law on dangerous products....

This is a description of the kit:


Manufacturer name Lamotte
Range 6, 8, 10, 20, 30, 40, 50 ppm
Measures Potassium
Number of Tests 100

I don’t want to alway buy that stuff but I like to learn how potassium behave in term of consumption ect.

I will not tell my wife....:icon_mrgr
 

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If it is dangerous goods, then how can we buy it in Canada? I would be very interested in finding out how potassium behaves in our aquariums.
 

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Discussion Starter · #6 ·
Dangerous stuff???

It is class as a dangerous product. Maybe because I have a company it’s easier for me to buy. Anyway with this kind of price, no wonder it is not carried in your corner pet shop...
 

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We're talking about the test kit not pure Potassium metals , I hope.
Well, I was just kidding around, but Sympley did say "I would be very interested in finding out how potassium behaves in our aquariums." A test kit wasn't mentioned.:icon_bigg

This one is great. It's all the alkali metals in water except for Francium:
http://youtube.com/watch?v=EKpAp2XASpw&mode=related&search=

Anyway, Aquariumlandscapes.net has a potassium test kit but it's another one of those turbitiy type of test kits that's a little hard to work with, I've been told. You can see it by going to the product overview or product search. It's Price: $ 30.00 Order no.: 999-200 : https://ssl.perfora.net/www.aquariu...nid=154626f82d90ae6/shopdata/index.shopscript
 

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Hey, hey, hey, be nice, I mean the test kit for potassium....by the way should I take my fish out before I try these experiments in my aquarium...:biggrin:
 

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Hey, hey, hey, be nice, I mean the test kit for potassium....:biggrin:
I know that you were talking about test kits and I was just kidding around. I just like the alkali metals. Do you think that Canada may view any sort of potassium as dangerous because of the way it reacts with water?
 

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It's not the potassium that is dangerous - it is the reagent used to react with the potassium. Potassium is usually measured by precipitation with tetraphenylborate MSDS, though that is only a mild health hazard.

Kevin
 

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I use colorimeter methods, these offer much higher precision.

We used the K+ Lamotte test, what? I guess it's 9-10 years ago now.
They work but are woefully inaccurate as is the AL version over the ranges of interest. Generally 10-50ppm or so.

They are turbimetric and you look through a tube etc and it's not that easy to tell between 20 and say 30ppm.

I approached things another way after that until I got a nice colorimeter(these run about 180$ for a K+ only unit, and then the cost of the reagents, I suggest getting a multiparameter unit personally).

I simply did a mass ratio analysis to see if we had any deficiencies.
See here over at AC plant forums for more info.

We also did a similar approach on the APD years ago and folks had about 20-50ppm ranges. Adding more K+ was golden and the solution to everything it seems to many at the time.

As long as it was non limiting, that was true it seemed and still is today. I've gone back and tested the K+ over the higher ranges, 50-80 ppm and not found any detriment to plants.
If you do water changes, it's not likely it'll ever get that higher even with K2SO4 dosing on top of say, EI.

If you use solely KNO3, most target about 20-30ppm.
Adding some GH booster or K2SO4, about 30-50ppm.

If you are interested, plants have a LATS and HATS systems for uptake and the higher levels are more efficient for the plant to maintain higher growth rates.

Plants can and will adapt to high and low CO2 as long as it's stable, the same is true for K+, NO3, PO4 etc..........

What happens is folks often bob between high and low pretty much confusing the plant.

Then they have trouble and blame things on a poor old innocent nutrient:)

Be careful there.

Regards,
Tom Barr
 

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I have never seen a liquid color test for potassium that could be measured with a colorimeter. I'm not saying they don't exist, but I've never seen or heard of one, or know where one could be purchased. Potassium is usually tested by measuring the turbidity that is created by adding tetraphenylborate to the sample with a small amount of sodium hydroxide added. (That's how the Lamotte kit works.) It can be measured with a turbidimeter, but only accurately from 0 to 10 ppm.

I have found the Lamotte test kit to be quite accurate. Tom keeps saying they are inaccurate, but I am just not seeing that on my end. I tested the kit with RO/DI water and ACS grade potassium sulfate, potassium carbonate, and potassium bicarbonate, and I get accurate and repeatable results every time.
 

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So because you have never seen one it must not exist. And you question someone who has actually used one?

A simple check at the LaMotte web site would have shown you that they exist. But I would guess that's not enough proof for you.

I have found the Lamotte test kit to be quite accurate. Tom keeps saying they are inaccurate, but I am just not seeing that on my end. I tested the kit with RO/DI water and ACS grade potassium sulfate, potassium carbonate, and potassium bicarbonate, and I get accurate and repeatable results every time.
What was the testing methodology? Did you dose a known quantity into the water then test? Thereby validating what you already knew. Or did you dose an unknown quantity and find out how much you dosed? And how did you verify that test?

Testing method here is everything.
 

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Rex Grigg said:
So because you have never seen one it must not exist.
Please learn to read before putting words in my mouth:

Hypancistrus said:
I have never seen a liquid color test for potassium that could be measured with a colorimeter. I'm not saying they don't exist,
Rex Grigg said:
A simple check at the LaMotte web site would have shown you that they exist. But I would guess that's not enough proof for you.
Lamotte Potassium Test Kits:

http://www.lamotte.com/pages/wawa/ind-kits/potasium.html

Turbidity test. Not a color test. If you're so smart, post a link to a liquid postassium color test kit. I'm not saying they don't exist, but I've yet to see one, read an explanation of the chemicals used and how they work, and see one available for purchase some place.

Rex Grigg said:
What was the testing methodology? Did you dose a known quantity into the water then test?
Yes. Known quantity (20 ppm) using a formula. Used Lamotte Potassium Test Kit, kit read 20 ppm.

Once again, a rude and confrontational post from Rex Grigg. I swear, reading your posts sucks all the enjoyment right out of the forums and the hobby, for me anyways.
 

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From Tom's post that you responded to:

I approached things another way after that until I got a nice colorimeter(these run about 180$ for a K+ only unit, and then the cost of the reagents, I suggest getting a multiparameter unit personally).
Your response:

I have never seen a liquid color test for potassium that could be measured with a colorimeter.
LaMotte Link

If the Colorimeter doesn't use liquid test then what does it use?

What I have noticed is you like to evade and change the subject when you are backed into a corner. You make statements and then when asked to prove them you either change the subject or just ignore the question.

And your testing methodology is suspect. If you know there is 20 ppm then you will read an iffy result as 20 ppm. You may not do it consciously but that's what happens.

You hear hoof beats at the Kentucky Derby you think horses.
 
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