Help with some doubts.

[get]

Hello:

I have some problems regarding the composition of the fertilizer.

If necessary I will put the commercial names.

I have a fertilizer that have a concentration of 5-0-1.
Putting 1ml per liter, i get a concentration of 230ppm. It is correct to fertilize Paphiopedilum?.
To add phosphorus, i buy a phosphorus fertilizer 20%.
For now, what I did was dilute 0.5ml in 50ml of water giving a concentration of 1000ppm (this course is 20%, haha), then i added 10ml of this mixture to 1 liter rainwater, obtaining an increase of 13 ppm .
To this liter I added 1ml of the fertilizer 5-0-1 and it gives 230 ppm.

I'm doing well? And how I can improve this?
What would be the best combination 5-2-1 or 5-1-1. And how would you do?

Also I have some doubts about the epson salt and dolomite, the epson salt what amount is added? my measurements give 750ppm by adding 1g in a liter of water.

Dolomite leave it for another time, as this related to the pH and accumulate too many questions!

Thank you very much.

 

[ALToronto]

I don't see how adding 1 ml of fertilizer to plain water gives 270 ppm, but adding the same 1 ml of fertilizer to the same volume of water with phosphorus gives a lower ppm reading. Something is off.

 

[get]

Hi ALToronto, i make a mistake copying the data.
1ml of 5-0-1 give me about 230 in 1liter of rainwater.

Can the pH of the water something to do with variations in the measurements?

Sorry for the mistake, i edit it now.

 

[Rick]

Hi ALToronto, i make a mistake copying the data.
1ml of 5-0-1 give me about 230 in 1liter of rainwater.

Can the pH of the water something to do with variations in the measurements?

Sorry for the mistake, i edit it now.

So when you add 1ml per liter to get the 230 ppm is that measured as TDS/conductivity?

 

[get]

Hi Rick:

Yes, that is the measure that gives the tds meter.

If I'm not mistaken N supply would 11-12 ppm. According to the forum I read, is a very small amount, no, right?

 

[get]

Please, anyone can say me if these % of N is correct?
And if i add these 13 ppm of P is about 2,5 ppm of P, isn´t this measure too small?

Regards for all!

 

[DavidCampen]

You keep confusing things by switching back and forth between TDS expressed as ppm and actual ppm by weight. These are 2 very different things.

Calculating ppm by weight:

By diluting your 20% phosphorus solution 1:100 (0.5:50) you get a phosphorus solution that is 2000 ppm phosphorus.

Your 5-0-1 fertilizer is 50000 ppm nitrogen and 10000 ppm.

So if you take 10 ml of the 2000 ppm phosphorus solution and 1 ml of the 5-0-1 and add water to make 1 liter then you will have a solution that contains
50 ppm nitrogen, 20 ppm phosphorus and 10 ppm potassium.

TDS as measured by a hand held TDS meter is not really a measurement of Total Dissolved Solids. It is actually a measurement of the electrical conductivity of the water which is then converted to the ppm of calcium carbonate that would have to be dissolved in pure water to give the electrical conductivity that was measured.

 

[Trithor]

TDS as measured by a hand held TDS meter is not really a measurement of Total Dissolved Solids. It is actually a measurement of the electrical conductivity of the water which is then converted to the ppm of calcium carbonate that would have to be dissolved in pure water to give the electrical conductivity that was measured.

What is the practical use of EC then?

 

[DavidCampen]

What is the practical use of EC then?

It gives an approximation of the amount of dissolved ionic solids. If the dissolved solid in your water is mostly calcium carbonate then it would be very accurate. If the dissolved solids in your water is not calcium carbonate but is known qualitatively and you know some chemistry then you can adjust the TDS value to be fairly accurate.

I use my TDS meter for several things:

* To check that my RO system is functioning properly, the TDS reading should be less than 10.

* As a check to verify that I have not made an error when formulating a fertilizer solution concentrate. I can calculate approximately what the TDS value should be for a dilution of the concentrate and use the TDS reading to check this.

* As a check to verify that my chemical metering pump is adding the proper amount of nutrient concentrate to the water going to my watering wand. In the step above I prepared a known dilution of the nutrient concentrate and measure the TDS so I know what the TDS of my watering solution should be after the chemical metering pump has added the concentrate to the RO water and I check this everyonce in a while.

 

[Trithor]

Thank you David.

 

[get]

You keep confusing things by switching back and forth between TDS expressed as ppm and actual ppm by weight. These are 2 very different things.

Calculating ppm by weight:

By diluting your 20% phosphorus solution 1:100 (0.5:50) you get a phosphorus solution that is 2000 ppm phosphorus.

Your 5-0-1 fertilizer is 50000 ppm nitrogen and 10000 ppm.

So if you take 10 ml of the 2000 ppm phosphorus solution and 1 ml of the 5-0-1 and add water to make 1 liter then you will have a solution that contains
50 ppm nitrogen, 20 ppm phosphorus and 10 ppm potassium.

TDS as measured by a hand held TDS meter is not really a measurement of Total Dissolved Solids. It is actually a measurement of the electrical conductivity of the water which is then converted to the ppm of calcium carbonate that would have to be dissolved in pure water to give the electrical conductivity that was measured.

Hi:

Too much thanks David.
You´re right. I´m wrong about my thinking.

i dont know where the date comes from:
"Your 5-0-1 fertilizer is 50000 ppm nitrogen and 10000 ppm."
How convert it to ppm?

If i understand correctly, I have to add Mg to the fertiliced, in the same way that P. I use Epson salt to make these.
If i take 1 gr of Epson salt and i diluite in 100ml of water, i make a solution that have 1660ppm of Mg.
So for add about 30ppm of Mg i think, that i add 20ml of the Epson salt solution...is correct?

I know I have much to learn, but I hope with your help to do it right.

Thanks.

 

[DavidCampen]

i dont know where the date comes from:
"Your 5-0-1 fertilizer is 50000 ppm nitrogen and 10000 ppm."
How convert it to ppm?

1% = 10000ppm

If i take 1 gr of Epson salt and i diluite in 100ml of water, i make a solution that have 1660ppm of Mg. ... So for add about 30ppm of Mg i think, that i add 20ml of the Epson salt solution...is correct?

According to my calculations, Epsom Salt is about 10% magnesium so 10 grams of Epsom Salt dissolved in 1 liter of water gives a solution that is 1000ppm magnesium. So then 30 ml of this concentrated solution per liter would give you 30ppm magnesium.

 

[get]

Thanks.
In the label of epson put: 16.66%Mg and 32.5%S. for these reason i make the solution.
How you calculate the 10% of Mg?

I know is messy, but is the only way that i find to try it.

And another question, you find reasonable all those datas of N,P,K,Mg to add in all irrigation water or should i alternate between waterings?

And again, thanks so much for your time!

 

[DavidCampen]

Epsom Salt is magnesium sulfate heptahydrate (MgSO4-7H2O) the and the formula weight is 246. The atomic weight of magnesium is 24 so 24/246 = 9.8% but if the label says 16.7% then use that value; the material must be not the heptahydrate.

I use about 50 to 75 ppm of nitrogen every time I water but then most of my plants are not paphiopedilums and every time I water I use enough so that the water drains through the pot. Almost all of my plants are in coarse bark, inorganic materials or mounted.

 

[get]

Hello David:

Thanks again, :clap: hopefully going in the right direction!!
You´re right in the 10% of Mg, the 16,66 is MgO and 32,5% de SO3.
So...i make your Mg solution.
I think, that my fertilicer stay like these:
N 5,P 2,K 1, Ca 5, Mg 3. The other micronutrients are similar.

If you think that these concentration are wrong, please let me know. I think that dont have the correct N, but i can´t make it better.

If someone know a european distributor, let me know!

Regards