DIY Nutrients formulations, recipes, chemistry etc.

[Nifty_PoT]

I have a question i hope some1 can answer, Im busy trying to "Calibrate" hydrobuddy for my individual salts . I am going to dissolve 1g in 1liter of water of all my salts to compare the ppm readings with what hydrobuddy gives.
So far i have done Calcium ammonium nitrate. My problem is hydrobuddy says 346.5ppm in 1 liter whereas the actual reading i got was 693ppm-65ppm of the tap water to give 628ppm. The percentages on the fert bag is 1,5%NH4 14% NO3 and 19.5% Ca. How do i get the hydrobuddy ppm to match up with my actual readings? ( i used 1 liter volumetric flask and 0.001g scale ) Any help will be much appreciated

 

[Avenger]

How do i get the hydrobuddy ppm to match up with my actual readings?

you won't, because ppm TDS meters don't measure ppm, they measure EC and mathmatically convert it to ppm using a standard conversion factor based on one of several standard electrolytes.

which is why you should not use TDS meters but rather an EC meter.

At any given concentration, different salts in solution conduct electricity better or worse than any other salt in solution.

 

[BCMaster]

What do you guys think of this profile

N 136
P 79
K 179
Mg 66
Ca 117
S 58

 

[Nifty_PoT]

you won't, because ppm TDS meters don't measure ppm, they measure EC and mathmatically convert it to ppm using a standard conversion factor based on one of several standard electrolytes.

which is why you should not use TDS meters but rather an EC meter.

At any given concentration, different salts in solution conduct electricity better or worse than any other salt in solution.

Hi Avenger , Thanks for your reply. So what happens if i go and use an EC meter and the readings still dont match up? Should i not worry about it? Will my final EC not be way too high?

 

[BasementBreeder]

Nifty

Hydrobuddy's predicted EC has always matched my meter within .1 mS/cm.

 

[Avenger]

As BB said the predicted EC from hydrobuddy is a pretty close calculation, so long as you set the water quality parameters.

 

[Nifty_PoT]

Okay cool! Thanks for the help , Ive been playing around and i notice the EC values "converted " at 0.5 convertion to ppm doesnt realy tell you much , Also interesting to see how even though the ppm in formula is say 350 for CaNO3 the ec value of that according to hydrobuddy is 0.9ms/cm , I now understand that is just because different salts may conduct electricity better or not so good ect. So would i be right in saying that you cant covert EC to ppm like that and expect it to match? cause then 0.9EC would be 450ppm(@0.5 conv) wich it is not?
As it is only providing 350ppm in formula and the other 100ppm is just like there because of better electrical conductivity but its not providing actual food to the plant? Still trying to totally wrap my head around this .

 

[Ultra Current]

Great thread! Been trying to figure this out for a while. Now it should be easy!

 

[Nifty_PoT]

Hey there. I got an EC meter . Problem is its telling me exactly what i got from my ppm meter. 1 gram CaNo3 should be 0.9ms/cm according to hydrobuddy but im getting 1.35-0.12(tap) =1.23ms/cm
so its off by 0.33.. This is realy frustrating , can anyone help please!

*edit , just got this link for the Cano3-
http://www.canitratedirect.com/Calcinit PDS.pdf
Turns out the 1.2ms/cm reading i got was spot on . So how do i get hydrobuddy to give me 1,2 and not 0.9?
*edit again lol , so i got hydrobuddy to read 1,2 EC after changing the purity of the salt to 130%, Not sure if i should be doing this, but it seems like i should lol

 

[BasementBreeder]

Nifty

Interesting that hydrobuddy's estimate for CaNO3 is so far off and yet still gives me accurate(+/- .1) estimates for the entire nute solution. Some of the other salts must be overestimated.

I wouldn't change the purity of the salt(unless you know what the true purity is). This is going to throw off the ppm of Ca and N. ie, it might say you have 130 ppm of N when in reality you only have 100.

Anyway, I wouldn't stress about hydrobuddy's estimated EC. Focus on providing the correct amount of each nutrient. That's far more important than what the EC reading is.

 

[Avenger]

The estimated EC from hydrobuddy is just a calculation. Daniel used the method explained in this article:
http://www.currentseparations.com/issues/18-3/cs18-3c.pdf

It is hard to accurately calculate the EC of solutions. There are just too many variables. Pretty close is as good as it is gonna get. i wouldn't change the putiry to match my pens reading. Use them both, the calculated and measured(calibrated) to make decisions.

I check the single salts KNO3, K2O4, KH2PO4, KCL and cnd checked the calculated EC from hydrobuddy compared to the published EC from the salt manufacturer like you did for CaNO3 and the KNO3 and Kcl were low similar the the CaNO3, however the K2SO4 and KH2PO4 were pretty close, with-in a few hundredths.

 

[Nifty_PoT]

Cool, thanks for all the help, il be focusing on providing the correct info of the salts to the program and not rely so much on the predicted EC then.

Hey Avenger, yeah thats not cool! i was hoping that hydrobuddy would be a accurate way to make my mixes but now im not so sure. Dont realy wana try and figure out how to do all these calculations manualy lol
Also hydrobuddy gives me 0 EC for any amount of boric acid mixed in a solotion? surely that cant be correct? I thought boron coducts electricity?

 

[blueberrydrumz]

Hello folks

Here's a great example of how simple a lot of nute formulations are, this is the formula for original Hammerhead (the 0-9-18 labelled one), courtesy of mullray:

Mono Potassium Phosphate 107g
Potassium Sulphate 68g
Magnesium Sulphate 4g

Those salt values are for one litre of stock solution, basically you put the salts into a litre bottle, add distilled water and shake till it all dissolves et voila, you have a litre of Hammerhead for a tiny fraction of the retail cost.

Hi, good thread & good ethics behind it...
but i think there might be something wrong with this formula...correct me if im wrong, but lets have a look..
oh yeah its always important to state whot % ratios the salts have that are been used

i get for one Liter of Hammerhead 9/18 following mix
1g/liter actual ppm
9% Phosporus = 90 X .436 = 39.24ppm
18% Potassium= 180 X .83 = 149.4ppm
Directions on the bottle are
Add Hammerhead to your reservoir at a rate of 2 ml per Litre (1.5 tsp per gallon)
so a 1L bottle will give you 1000ml/2ml=500Liters of the correct solution
MKP 0%-52%-34% 78.2g
Potassium Sulphate 0%-0%-50%(18%S) 91.8g
be good if some expert can verify this.. thx

 

[blueberrydrumz]

any1?

 

[asa77sol]

Mono Potassium Phosphate 107g
Potassium Sulphate 68g

0-6-7

9% Phosporus = 90 X .436 = 39.24ppm
18% Potassium= 180 X .83 = 149.4ppm

It's true.

MKP 0%-52%-34% 78.2g
Potassium Sulphate 0%-0%-50%(18%S) 91.8g

It's means 0-4-7

P from MKP, the P is 52%.
9/52= 0,173--->173g/L

K part from the MKP(0-52-34,4)
0,173*34,4%=5,95%
18-5,95=12,05%

K part from the K2SO4(0-0-50)
12,05/50=0,241--->241g/L

So, (173g MKP + 241g K2SO4)/L=Hammerhead
0-9-18

 

[blueberrydrumz]

0-6-7

It's true.

It's means 0-4-7

P from MKP, the P is 52%.
9/52= 0,173--->173g/L

K part from the MKP(0-52-34,4)
0,173*34,4%=5,95%
18-5,95=12,05%

K part from the K2SO4(0-0-50)
12,05/50=0,241--->241g/L

So, (173g MKP + 241g K2SO4)/L=Hammerhead
0-9-18

hi,
can you please explain your calculations,
because if:

173g/L = 173000mg/L = 173000ppm in 1 L

2ml gives the ppm from above so it doesnt add up

173000ppm / 500 = 346ppm that would be wrong

arghh .. im tired... good night

 

[BasementBreeder]

blueberry,

I'm coming out with similar numbers to asa.

0-9-18, contains 90g/L P2O5 and 180g/L K20
MKP(0-52-34) is our only source of P, so we need the MKP to provide 90g of P2O5
MKP is 52% P2O5, so .52*(x)=90g
x=173g of MKP

The MKP also provides K2O
173*.34= 58.8g of K20

180-58.8=121.2g of K2O still needed from K2SO4

 

[blueberrydrumz]

blueberry,

I'm coming out with similar numbers to asa.

0-9-18, contains 90g/L P2O5 and 180g/L K20
MKP(0-52-34) is our only source of P, so we need the MKP to provide 90g of P2O5
MKP is 52% P2O5, so .52*(x)=90g
x=173g of MKP

The MKP also provides K2O
173*.34= 58.8g of K20

180-58.8=121.2g of K2O still needed from K2SO4

ok, still doesnt make sence & dont know how you get these nbrs here goes again lol...

Here are some facts ive learned & gathered from other forums:

P is converted from P2O5 at a rate of 43.6% useable (HPO4) P.

K is converted from K2O at a rate of 83% useable (K+) K.

9% Phosporus = 90 X .436 = 39.24ppm actual ppm

18% Potassium= 180 X .83 = 149.4ppm actual ppm if you put 1ml/L so if we have 9% P = 3.924% actual P


directions for Hammerhead are 2ml/L
so we get 500L of solutioin so that should be a dilution factor of 1000

39.24ppm*1000(dilution)=39240ppm of P in 1 L of Hammerhead

149.4ppm*1000(dilution)=149400ppm of K in 1 L of Hammerhead

MKP(0-52-34) is our source of P
so 52% * 10 = 520 39240ppm/520=75.46 g/L
so 75.46 g has 25.66 g = 25656ppm of K we need 149400ppm of K
149400 - 25656 = 123744 ppm still needed so 50% * 10 = 500
123744ppm/500= 247.48g thats close to whot asa77sol got

MKP 75.46g
K2SO4 247.48g

... like i say im no expert... but strange that every1 gets different figures...
i used cannastats for my first post... now i calculated it by hand and they both dont add up lol but this should be correct... please help if some1 can -- bless

 

[Avenger]

MKP(0-52-34) is our source of P
so 52% * 10 = 520 39240ppm/520=75.46 g/L
so 75.46 g has 25.66 g = 25656ppm of K we need 149400ppm of K
149400 - 25656 = 123744 ppm still needed so 50% * 10 = 500
123744ppm/500= 247.48g thats close to whot asa77sol got

MKP 75.46g
K2SO4 247.48g

MKP is 52% P2O5 or 22.69% P

22.69 * 10= 226.9

39240/ 226.9 = 173

 

[blueberrydrumz]

MKP is 52% P2O5 or 22.69% P

22.69 * 10= 226.9

39240/ 226.9 = 173

Avenger.. cool yeah i forgot that
MKP has only 22.67% P - 52 * 0.436 = 22.67% so makes sence 39240 / 226.9 = 173grams
do i also have to work out the K from those 173g like this:
173 * 0.34 = 58.8g of K20 58.8 * 0.83 = 48.80g of K ??
K2SO2 50% = 50 * 0.83 = 41.5% K
so 149400ppm / 415 = 360 grams needed 360 - 48.8 = 311.2
like i say im new to this and just trying to get my head round it...
thx for all the help guys... i dont take things for granted..
i always need to find out for my self and glad i did... the formula stated at the beginning of the thread is totaly wrong...
bless