What is KH2PO4?

[Bmeasure]

Is KH2PO4 Mono Potassium Phosphate?

Also, what is the fert I have from www.litemanu.com called "Tripple Phosphate 0-45-0", and is this a good source of PO4 for a planted tank? I have noticed it seems to be VERY potent compared to the "Mono Potassium Phosphate" from the same dealer. Thanks.

 

[coralnerd]

Is KH2PO4 Mono Potassium Phosphate?

Also, what is the fert I have from www.litemanu.com called "Tripple Phosphate 0-45-0", and is this a good source of PO4 for a planted tank? I have noticed it seems to be VERY potent compared to the "Mono Potassium Phosphate" from the same dealer. Thanks.

What you have is monopotassium phosphate, otherwise known as potassium dihydrogen phosphate. Phosphate exists as PO4---, HPO4-- or H2PO-, depending on the pH of the solution. In highly acidic condtions (which you won't have in your tank) it also exists as phosphoric acid (H3PO4).

I'm not a plant expert, so anyone who knows better should correct me here, but based on my chemistry knowledge, whichever form of phosphate you use will supply the same amount of phosporous per molecule. At pH 7 most phosphate will exist as biphosphate (HPO4--) and dihydrogenphosphate (H2PO4-). These species will form spontaneously until chemical equilibrium is reached, so it doesn't really matter whether you supply the phosphorous as HPO4-- or H2PO4-, the relative concentrations will end up the same.

Since H2PO4- is slightly heavier than HPO4--, you will need to add slightly more of it (in terms of the mass of undissolved salt) to supply the same amount of phosphorous to your plants.

 

[VeryLongFishPoo]

your right, it is a little heavier, but not very much at all.


****Since H2PO4- is slightly heavier than HPO4--,

2+32+16*4= 96

1+32+16*4= 97

noticing one is a little heavier, even though it's 1%, suggests you used to do a bit of chemistry in the past, eh? :coffee2:

 

[coralnerd]

noticing one is a little heavier, even though it's 1%, suggests you used to do a bit of chemistry in the past, eh? :coffee2:

Yeah, more than a bit actually. . . the 'nerd' in my name is there for a reason.