Ei - Right Compound?

[montyII]

Bit of a techy chemistry question.
I just received my 2 tubs of powder in the mail to start my EI light dosing.
I ordered KNO3 and KH2PO4, one of the tubs contains "MPK, P2O5 (52%), K20 (34%). Does this mean I have KH2PO5, not KH2PO4? And does that cheeky extra oxygen molecule make any difference?

Ta.

 

[Dave Spencer]

Bit of a techy chemistry question.
I just received my 2 tubs of powder in the mail to start my EI light dosing.
I ordered KNO3 and KH2PO4, one of the tubs contains "MPK, P2O5 (52%), K20 (34%). Does this mean I have KH2PO5, not KH2PO4? And does that cheeky extra oxygen molecule make any difference?

Ta.

P2O5 is Phosphorus Pentoxide and K2O is Potassium Oxide, constituents of Monopotassium Phosphate (KH2PO4) fertiliser. I`m not sure where you are getting KH2PO5 from.

Dave.

EDIT: Forgot to mention that with the KH2PO4 you bought, you are using the right stuff.

 

[montyII]

Excellent, thanks Dave.
I think I got "KH2PO5" from not having been near chemistry in about 15 years and just making it up as I went along.

 

[SuperColey1]

Yeah I can confirm I but MKP mono potassium phosphate at work and it is KH2PO4

Andy

 

[montyII]

Cheers for that, Andy. Not sure if I'm kidding myself or not, but the plants seem to be enjoying it already!

 

[plantbrain]

As long as you stay on top of CO2, adding PO4 can be done pretty liberally and if you where limited PO4, then you should see rapid improvements, like within 1-4 hours.

Note: this means your tank will use more NO3, more K, more CO2 and traces, but you wanted more growth anyway.........that's why we add CO2 etc and more light...........

Regards,
Tom Barr

 

[montyII]

Thanks Tom.
I'm using Excel, not CO2, and dosing according to the "Intro to non CO2 Excel tanks" article on your site. Seeing as the amount of carbon in my tank is limited compared to using CO2 I guess I should stick to the amounts of ferts suggested.

P.S: I asked this on the barrreport but I might as well ask here too: is it worth me increasing my light from the 1.5wpg I have now to the maximum 2wpg suggested for non-CO2 setups? (I currently use 2X30w T8s and was thinking of adding another 15-20W reflector to my tank).