# KH2PO4 not good ?



## wisiu (19 Dec 2013)

Hello All


I am wondering if you can help me with my issue, I have some KH2PO4 ordered from one of dry salts online shops. I have dissolved 1.63g of KH2PO4 in 500ml of water to dose 40ml of this solution to my 70L tank. I wanted to see how my Nutrafin PO4 test will react when I use it straight on the solution. I have poured 5ml of my fertilizer to the probe and added required drops of tester, to my surprise the test didn't turn to blue color at all which means that PO4 is complete zero in my DIY fert. Now the question is if there is something wrong with my test or with salt ? When I test my tap water the test shows dark blue. Could you please try to test your DIY ferts and see if your test will show anything ? Also when I test my aquarium water the test shows between 1-2 ppm.

Thanks.


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## sanj (19 Dec 2013)

Are you thinking that your KH2PO4 salt might actually be somthing else. I guess it is possible they could have confused it with KNO3, although they are a slightly different shade of white and texture. have you tried testing for nitrate?


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## ian_m (19 Dec 2013)

Try soaking string/blotting paper in potassium nitrate solution, drying it and then lighting it (carefully). Nitrate is an oxidising agent, phosphate isn't.


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## wisiu (19 Dec 2013)

I have also KNO3 home so I will look if they look different, I was using dry ferts for more than a year and always had a problems with plants so it might by the reason.


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## anasarka (19 Dec 2013)

try a friend KH2PO4
If the test register it, you have to buy another KH2PO4
If the test does not register it you have to buy a new test


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## Iain Sutherland (19 Dec 2013)

Could be wrong but think Clive mentioned before that dry po4 won't show on tests, something to do with the tests not actually measuring for po4..?? 
That's and test kits suk balls! 


Sent from my iPhone using Tapatalk


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## Rasmusm (20 Dec 2013)

Test kits suck.. Just dose it and dont think more about it  if it was kno3 you would be able to smell the difference


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