Monopotassium Phosphate (MPK) vs Potassium Phosphate (K)?

Star Dog

Well-Known Member
Yes Im using Dry mix. I dont know the conversion rate. I also get my Calcium from Calcium Nitrate, which is 20% Calcium. WHich negates my need for Cal/Mag as I get my Magnesium from Epsom Salts, as well as Sulfur.
I will pick it up in time I'm just unfamiliar with it all atm.

I'm not sure if this would be ok... I could mix up a gallon of canna then add 0.66g mpk then test the ec, that should give me a ball park ec figure... I think?
 

jimihendrix1

Well-Known Member
I will pick it up in time I'm just unfamiliar with it all atm.

I'm not sure if this would be ok... I could mix up a gallon of canna then add 0.66g mpk then test the ec, that should give me a ball park ec figure... I think?

Sounds logical. I dont see why it wouldnt work.
 

jimihendrix1

Well-Known Member
Don’t forget that 0.66g was for @jimihendrix1 5 gallon mix!

The .66 Grams is what is recommended for 1 gallon at full strength.

I grow in Promix BX, and feed with each watering, so I dilute the mix because of the frequent feed, and type of medium. I dont feed full strength.

The above mix is for each gallon of water. I just use a diluted ratio.

Notice the instructions say Per Gallon of water.


4-20-39 Recipe – For a great baseline would be 2 grams per gallon water for 4-20-39, 2 grams per gallon of water for CaNO3 and 2/3 that amount of MgSO4 (1 1/3 gram per gallon of water). We suggest you try to keep your pH right around 6.2 for the duration but some fluctuations are not uncommon. During middle weeks of flower, you can add 1/3 the amount of MKP for extra K (potassium). Certain strains can tolerate a higher EC than others and you are welcome to push those strains if you like but we feel the base mixture will do a great job,
 

jondamon

Well-Known Member
The .66 Grams is what is recommended for 1 gallon at full strength.

I grow in Promix BX, and feed with each watering, so I dilute the mix because of the frequent feed, and type of medium. I dont feed full strength.

The above mix is for each gallon of water. I just use a diluted ratio.

Notice the instructions say Per Gallon of water.


4-20-39 Recipe – For a great baseline would be 2 grams per gallon water for 4-20-39, 2 grams per gallon of water for CaNO3 and 2/3 that amount of MgSO4 (1 1/3 gram per gallon of water). We suggest you try to keep your pH right around 6.2 for the duration but some fluctuations are not uncommon. During middle weeks of flower, you can add 1/3 the amount of MKP for extra K (potassium). Certain strains can tolerate a higher EC than others and you are welcome to push those strains if you like but we feel the base mixture will do a great job,
Sorry my bad.

i know @Star Dog is U.K. based and we tend to work I’m litres which is why I mentioned it.
 

Star Dog

Well-Known Member
Sorry my bad.

i know @Star Dog is U.K. based and we tend to work I’m litres which is why I mentioned it.
Yes I'm with you there, I'm planning on mixing up a gallon at 0.66g to see what the ec is then take from there.

I've got 2 plants I don't care about (loosely speaking) so I intend to feed them at elevated levels of mpk and the rest of the crop at maintance levels.
 

jondamon

Well-Known Member
Yes I'm with you there, I'm planning on mixing up a gallon at 0.66g to see what the ec is then take from there.

I've got 2 plants I don't care about (loosely speaking) so I intend to feed them at elevated levels of mpk and the rest of the crop at maintance levels.
I’ll keep saying it as I find it a big help but dissolve 14g of MKP into 100ml of water and use at 1ml per litre for 0.1EC increase lol.
 

Star Dog

Well-Known Member
I've done some calculations and 0.66g per gal (4ltr) works out at 0.165g per litre.

With 14g to 100ml that works out at 0.14g per litre to my calculations so the two are actually quite close if my maths is accurate.
 

Star Dog

Well-Known Member
I’ll keep saying it as I find it a big help but dissolve 14g of MKP into 100ml of water and use at 1ml per litre for 0.1EC increase lol.
I've got that but I intend to experiment and find out 1st hand myself what difference it really makes.
 

jondamon

Well-Known Member
I've done some calculations and 0.66g per gal (4ltr) works out at 0.165g per litre.

With 14g to 100ml that works out at 0.14g per litre to my calculations so the two are actually quite close if my maths is accurate.
No idea lol.

Thankfully a guy on here @spek9 helped me as he had a metric tonne of MKP and wanted to find max saturation point and see if he could get it to be 1ml per 1litre of concentrated solution to increase nutrient solution EC by 0.1 at that dilution rate.

He found 143g to 1litre was max saturation of the MKP in the water

so I reduced it to a more manageable amount for my requirements. Lol.
 

jondamon

Well-Known Member
I've got that but I intend to experiment and find out 1st hand myself what difference it really makes.
If this was me I would also be elevating those levels of Ca and Mg from the standard 5:2 of the canna Coco A/B as the additonal KP can play havoc with the rootzone if you go too strong.

And I found the additonal Ca helped with the CEC of the coco when feeding the MKP fairly strong.
 

Star Dog

Well-Known Member
If this was me I would also be elevating those levels of Ca and Mg from the standard 5:2 of the canna Coco A/B as the additonal KP can play havoc with the rootzone if you go too strong.

And I found the additonal Ca helped with the CEC of the coco when feeding the MKP fairly strong.
That's really handy to know I was planning to increase the mg and cal but not right away, I've not gotten around to working out a stock solution and wasn't in a hurry so I'll get on it asap.

Have you ever had any problems with precipitation mixing magnesium with mpk?

The plants I'm testing on aren't part of my crop I kept a couple extra to test mpk, calcium and magnesium on, I don't aim to hurt them but if i do there will something learned along the way.

Cheers!
 

jondamon

Well-Known Member
That's really handy to know I was planning to increase the mg and cal but not right away, I've not gotten around to working out a stock solution and wasn't in a hurry so I'll get on it asap.

Have you ever had any problems with precipitation mixing magnesium with mpk?

The plants I'm testing on aren't part of my crop I kept a couple extra to test mpk, calcium and magnesium on, I don't aim to hurt them but if i do there will something learned along the way.

Cheers!
To be honest with you I’ve not seen anything but this is what I’ve got.

plant magic calmag liquid
Epsom salts dry
Canna magnesium liquid
MKP dry

As you can see the only dry I do have is MKP and MgSO4.

the MKP I make a stock solution and the MgSO4 I tend to use during later flower +4weeks and I tend to mix one 0.1EC into my solution but I do it gradually pinch at a time in some luke warm water to help it dissolve until My res reads 0.1EC higher than it was.

I cant say with any certainty About precipitates as it’s only the MgSO4 that’s dry lol.

When mixing my Base A/B, MKP stock solution and the MgSO4 separately into my 25L refill container I don’t notice anything.
 

Onextremebuzz

Well-Known Member
I picked up a 25KG bag from my farmer supply store earlier in the summer, I do a lot of experiments and this is one of them. Be careful it's potent 50 grams per 20 gallons of water creates a pretty decent solution I went as high as 75 grams. Use it once a week at the absolute max or depending on the plants are feeding anymore you will create a low pH environment and your plants will get iron magnese and aluminum poisoning as well as many other issues.
 
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