If potassium phosphate is 98% pure, what is likely to be the 2% impurity?

[skyshrimp]

I've ordered some on eBay from China to use in my aquarium.

I'm not sure how it is make and wondered what the impurities would most likely be from the manufacturing process.

 

[PeroK]

You should have looked at the specification before you bought it! In any case, have you asked your supplier?

 

[Vanadium 50]

If it's important, you need to check, not guess (or ask us to guess). If we guess sodium phosphate and it turns out to be potassium cyanide, your fish will not do so well and then you will be sad.

 

[skyshrimp]

Thanks, I'll just use it for my plants then. It was only a few pounds.

This is written on the packaging.

KH2PO4 98%
Active ingredient: potassium dichlorophosphate 98%
potassium oxide 33.8% phosphorus pentaoxide 51%

From what I've read, phosphorodichloridate would hydrolyse into hydrochloric acid in solution.

 

[BillTre]

In my experience, it is not normal to add phosphate to an aquarium system.
It is usually not needed because phosphates are continually continuously being added to the aquarium in the food for the fish. It all ends up in the water eventually.
pH control is usually done with carbonates.
Plants will get the phosphates from the food after the fish poop.

 

[skyshrimp]

I have a high PO4 demand in my aquarium due to carbon dosing.

Why does the packaging state 98% potassium dihydrogen phosphate and 98% potassium dichlorophosphate?

Why is potassium oxide and phosphorus pentaoxide mentioned with percentages?

 

[Vanadium 50]

Why does the packaging state 98% potassium dihydrogen phosphate and 98% potassium dichlorophosphate?

Why is potassium oxide and phosphorus pentaoxide mentioned with percentages?

I've ordered some on eBay from China

Seems you have answered your own question.

 

[Borek]

Why does the packaging state 98% potassium dihydrogen phosphate and 98% potassium dichlorophosphate?

Because someone couldn't tell the difference between dichlorophosphate and dihydrogenphosphate?

Why is potassium oxide and phosphorus pentaoxide mentioned with percentages?

Not sure if it answers "why?", but expressing the composition of the fertilizer this way is quite common in the trade and allows for easy comparison of different mixtures/products.

 

[skyshrimp]

Thanks, it was the Translator app that was at fault (Chinese to English). I tried translating with the phone camera again and active ingredients translates as only potassium dihydrogen phosphate 98% now.