# Different results - Hagen x Sera KH test kits



## gabriel.basso (26 Oct 2010)

Hi,

I made a Drop Checker solution with Deionized Water and Sodium Bicarbonate. The procedure was to add a small amount of NaHCO3, shake it and test with Sera KH test kit until I got 4 dKH. The curious thing is that after all done I made a second test using Hagen test kit and the outcome was quite different! 

Sera (result unit: dKH, 1 per drop) = 4 reagent drops = 4 dKH x 17,9 = 71,6 ppm

Hagen (result unit: ppm, 10 per drop) = 5 reagent drops x 10 = 50 ppm x 0,056 = 2,8 dKH

A deviance of 43% ... isnt it too much? I've tested again and again, all with the same results.
My first thought is that some of the test kits has expired.. guess the best thing to do is to buy another test kit   

cheers


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## ceg4048 (28 Oct 2010)

Or just buy 4dkh water...

Cheers,


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## Whitebeam (28 Oct 2010)

gabriel.basso said:
			
		

> A deviance of 43% ... isnt it too much? I've tested again and again, all with the same results.
> My first thought is that some of the test kits has expired.. guess the best thing to do is to buy another test kit


Welcome to the wonderful world of calibrating test kits 

Peter


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## gabriel.basso (29 Oct 2010)

ceg4048 said:
			
		

> Or just buy 4dkh water...
> 
> Cheers,



Havent found it around here yet... looked for this solution at chemist's shops, aquarium stores, etc.. but no lucky.



			
				Whitebeam said:
			
		

> Welcome to the wonderful world of calibrating test kits
> 
> Peter



i'd rather stay away from this world Peter... I'll keep trying to get access to the buying 4dk solution world!


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## Whitebeam (29 Oct 2010)

gabriel.basso said:
			
		

> ceg4048 said:
> 
> 
> 
> > i'd rather stay away from this world Peter... I'll keep trying to get access to the buying 4dk solution world!


But once you've bought some guaranteed 4dKH water you _can_ calibrate your tests kits, at least for the 4dKH setting   

Peter


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## gabriel.basso (29 Oct 2010)

Hadnt thought that way... so obvious    :?  You are right Peter, so I wont have to trash any of my inaccurate tests anymore!!   

thanks


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## amy4342 (30 Oct 2010)

> Havent found it around here yet... looked for this solution at chemist's shops, aquarium stores, etc.. but no lucky.



A few of our sponsors sell it - check out the banners at the top right of each page.


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