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xena_z4

What is the cheapest type of system to run & maintain?

xena_z4
14 years ago

For many years - off & on - I've researched growing herbs & vegetables hydroponically, but have been unable to settle on which way to do it. They each have their pros & cons, and it boils down to your personal preferences or what you can afford. Through my research, I've determined that whichever set-up I choose, I can either make it cheaper myself, or - if need be - buy parts as I can afford them.

My first set-up will be indoors with no more than a dozen plants, just to get my feet wet.

So my question is this: Which set-up is generally the cheapest to run & maintain? There's cost of nutrients, water, electricity, etc. For example: aeroponics needs electricity to run the pumps, but seems to need less nutrients & water; there are passive hydroponics that don't use electricity, but use more water & nutrients than aeroponics. Does the cost of running a pump offset the savings of nutrients & water?

The lighting isn't really a question here as I'll be using the same lights no matter which set-up I'll eventually end up using. I know that really good LED lighting can be costly to buy, but relatively cheap to run.

I know there are more variables involved & I don't mean to open a can of worms, or highlight my ignorance; but I can't seem to find any definitive information anywhere about this. Unless I missed a good website or another forum. In which case, please politely point me the way.

Sonja

Comments (26)

  • greystoke
    14 years ago
    last modified: 9 years ago

    there are passive hydroponics that don't use electricity, but use more water & nutrients than aeroponics.

    Passive systems using wicks work very well and don't waste any water.

    {{gwi:1012262}}

    The trouble with wicks is that they limit the water transport (unless you can put in more wicks)

  • kbhale
    14 years ago
    last modified: 9 years ago

    I recently went through the questions you asked. To go cheapest you need to grow what grows the quickest and easiest, basically salad greens and herbs. If you go tomatoes and peppers your going to need more time, energy and nutrient. Also the more time it takes to produce something eatable the more problems that can happen. I know your asking what system gives you the best bang for the buck but I think it comes down to what you grow can give you the best bang for your buck.

    This what I'm doing and it's working for me.

    I'm using 2 oz plastic shot glass filled with Perlite to start seeds. Once the seeds come up I feed them with a very week nutrient.
    (I'm using cheap dry nutrient: https://www.discount-hydro.com/productdisp.php?pid=50&navid=12 ) and having good results.

    Once the plants are big enough to transplant I move them to 9oz cups. That I place in a small plastic bin with an air stone. This is what I call my nursery. The nutrient here is about 650-750 ppm. You could just leave the plants here and harvest as they mature. Notice at the very end the Swiss chard to large to move. Parsely down there to.

    My grow beds are flood and drain (Ebb). I move my plants from the nursery to 20oz cups were they live in the flood and drain till eaten. The nutrient 750-1000 ppm. I'm growing different greens the nutrient might seem low but a few of my greens have burnt tips if I go higher.


    I'm producing enough to provide a salad for 3 people every other day. If my luck continues my systems will produce enough to pay for it's self within a year or two. figuring a $1.00 per salad.

    I'm working on transplanting once, instead of twice. Also switching to Hydroton.
    I am a NB here but this is working for me.

  • grizzman
    14 years ago
    last modified: 9 years ago

    xena z4
    It really depends on what you're growing. for herbs and salads, I would use a raft system. for tomatoes, I generally use DWC or a DWC/aero hydrid. for peppers I'll use NFT.
    for "getting your feet wet" the nutrients will be expensive as you'll not want to yet commit to bulk purchases. Hydroponically branded nutrients are expensive comparatively.
    electricity will run from $.01 to $.08/ day, USD based on $.10 / kilowatt-hour.
    Passive systems are lowest maintenance. simply water as you see the reservoir emptying. all the others require some means to change or at least check/modify/add nutrients to the reservoir.
    Here is a link to a passive low cost grower created by a fellow who used to post here.
    I like NFT and EnF (vs DWC or rafts) because the rez is seperate from the growing area and easier to tend to.
    Ultimately, it really is just a matter of preference. I like troughs versus tables because I think they're easier to organize, but that's just me. Others might like a rubbermaid top for its compactness. I used to love my aero/DWC hydrid, but now I'm more a fan of NFT.
    As you go through seasons of growing, you'll find or do things that will change what you like or not, so don't be too caught up on committing to doing it one way only.
    But for starters, I would recommend either a raft or DWC in a 5 gallon bucket, depending on what you want to grow.

    kbhale
    Have you tried running your nutrients at lower levels? I only run about 750 ppm for tomatoes and only around 600ppm for peppers.

  • kbhale
    14 years ago
    last modified: 9 years ago

    Have you tried running your nutrients at lower levels? I only run about 750 ppm for tomatoes and only around 600ppm for peppers.

    Yes I have for till a couple weeks back. Having a lack of knowledge about nutrient needs I searched the web and found this list. http://www.hydroponic-gardening.ws/plant-growing-data.html So I been slowly bumping up my nutrient level.

  • grizzman
    14 years ago
    last modified: 9 years ago

    kbhale
    Be wary of those recommendations. their ppm range for lettuce (560-840)are based on EC meter conversions. if you EC meter reads 1.0 at ppm 500, the 560 is correct. if it reads 1.0 @ 750, then 840 is correct. for my truncheon meter, I would be using the 560. I mixed up a tomato solution to 750ppm and got an EC of 1.5. 750 / 1.5 = 500 If your EC meter reads out in ppm, make sure you know which scale it is calibrated to (750 or 500) otherwise you may be giving too much or too little food.

  • lucas_formulas
    14 years ago
    last modified: 9 years ago

    About popular ppm charts and actual nutrient concentrations:

    First of all, I'd rather be careful with these charts of ppm requirements for different plants. I've seen this (same) chart at a multitude of sites, simply copied from somewhere. There is no reference where it provides from and how it was determined or established. Some are simply not correct: just take the 3500 ppm max for tomatoes. That would be 7 EC- that's enough to kill a horse (figure of speech)! I do not use any of these data before I have no cross-references that confirm them.

    And this chart is actually not based on EC conversion standards but is supposed to give a range (from-to) for different varieties or applications. They explain it at their website like follows:

    LETTUCE: A general nutrient PPM can be from 560 - 840 depending on the variety of lettuce being grown.style>

    If you have a closer look at all data from the chart, you'll discover that there is no actual correlation between conversion standards and figures. They obviously are supposed to show a range (from-to).

    And here are the correct EC standards;

    Hanna, Milwaukee 1 ms/cm (EC 1.0 or CF 10) = 500 ppm
    Eutech 1 ms/cm (EC 1.0 or CF 10) = 640 ppm
    Truncheon 1 ms/cm (EC 1.0 or CF 10) = 700 ppm

    Normally 500 ppm/1.0 EC is standard, if not specified otherwise.

    But we are not out f the mess yet, because one cannot measure the ACTUAL ppm content of all elements present in a nutrient solution with an EC meter. Because an EC meter measures the total dissolved solids in a liquid (nutrient solution) only. But every nutrient is composed by components and raw materials and not by pure elements. Every component has a different reading of EC per dissolved gr/liter. Hence the EC reading of the dissolved components in a ready nutrient solution does NOT correspond to the actual elemental content of a solution!

    An example perhaps makes it clearer and easier to understand:
    This formula
    N=165
    P=55
    K=280
    Ca=197
    Mg=55
    S=93
    Cl=70

    Has a total of 885 (+5) trace elements = 890 ppm
    890 ppm converted to EC (/500) equals 1.78

    But the actual reading of all dissolved solids in this formula is actually EC 1.96! That's a difference of 90 ppm. More than 10% and almost the total content of elemental P and Mg!

    How comes? Simply because there are other dissolved solids in the nutrient solution than the elements we have listed in our formula. They are contaminants from different kind and may vary from component to component.

    In fact the difference between ACTUAL content in ppm of listed elements and EC-reading of a nutrient solution varies by type of formula. How much actual ppm and transfered EC-reading will vary, actually depends on what (and how much of each) components are contained in a solution.

    I've tested all components (I use in my formulas) for their elemental content versus their actual ppm reading of total dissolved solids present in a solution.
    Example 1:
    Calcium Nitrate:
    1 gr dissolved in 1 L of water

    Total elemental ppm 341 = (EC 0.68)
    Actual EC reading of the same solution: (475 ppm) = EC 0.95

    Example 2:
    Potassium Sulphate;
    1 gr dissolved in 1 L of water

    Total elemental ppm 632 = (EC 1.26)
    Actual EC reading of the same solution: (775 ppm) = EC 1.55

    PS: Data shown here are measured and taken from specific components, they may vary depending on purity of other component (analyzed and tested product), either in elemental content or in total purity (impurity = contaminants with different solid content). To get your accurate data, you have to measure the actual component (product) that is used to compose a formula or nutrient solution.

  • alex818
    14 years ago
    last modified: 9 years ago

    lucas_formulas,

    Very informative and what you're saying makes sense. With all that being said, what is the general rule for measuring the correct levels? Do you run a measurement for each nutrient in separate containers then combine them? Sorry if that sounds like a newby question.. I am very new to hydroponics.

    Also, is it better to use an EC meter or a TDS meter? I see the EC meters selling for alot more than the TDS meters. Is there a particular device that is popular and known to be accurate that doesnt break the bank?

    Thanks,

    Alex

  • lucas_formulas
    14 years ago
    last modified: 9 years ago

    Hi Alex,
    Don't worry this is a really tricky and confusing topic and it's extremely difficult to lay hand on detailed and reliable Info or intel as well. And then again many people are overwhelmed with the data and the equations. Anything that turns around nutrient formulas can indeed be a tough nut to crack. It took me ages to understand the finer points and I had to learn it bit by bit!

    How to proceed to determinate the total dissolved solids needed in a nutrient solution, compared to- or instead of the actual elemental ppm of the formula? Sorry for sounding a bit formal here, but I guess it's necessary to not end up in confusion ...

    Well, it depends on if you are composing and making nutrients from raw materials, or if you are using ready from shelf.

    If you are using whatever commercial nutrients, it depends on if you have got a liquid or solid product. The easiest is to ask the manufacturer how much the total in ppm of every macro and micro element of 1 gr or 1 milliliter, dissolved in 1 Liter would equal. You must specify the total ACTUAL elemental ppm of the formula, NOT total dissolved solids or the sum of any solids, in 1 liter! Then it's your turn: you dissolve 1 gr or 1 ml of the product in 1 liter (best is to use 10 liter, actually). After that you measure the EC and compare both data (inquired actual elemental ppm - and ppm of all solids you have determined). That's how you get your coefficient (if there is a notable difference of course). If the manufacturer doesn't release these data, you have to deduce and calculate them yourself from the specs on the packaging. Unfortunately in most cases they will not be complete and maths can't be done accurately. NPK, alone isn't good enough as you may have guessed.

    In case you are cooking your own stew like I do, its more "lavish labor" but it's always accurate. You need to measure every single component as shown in the above post: 1gr/Liter (1gr/10 Liter) for every component. That way you determine a coefficient for every single ingredient (raw material) you use. After that you only need to multiply gram used per ingredient with your coefficient -divided by liters (actual ppm is always in relation to liter). The total of all ingredients will then give you the total of ALL Dissolved Solids contained in your ready nutrient solution in ppm. You then compare both and get the difference (as seen before). Well, the Total of all solids is what you use (aim for), instead of the elemental ppm of your formula. Here, you could also proceed like you did with the commercial product, but under the condition that you have a 100% accurately measured concentration of you brewed "soup"...(normally home brew doesn't come that way) Got it?

    Once you have determined every single data, you may put all that numbers in a spread sheet and go computerized from there. It's much simpler and quicker that way. To make your formulas there is more to know and to calculate, actually - but these are the basics you need to solve this particular end of the equation.

    A General role? I am not sure, as I have integrated the equation only recently in my spreadsheet. Gotta run a few calculus with various formulas. I'd say that (as far as I can see) it should turn around +10% to get actual ppm of the formula.

    I am not an expert about various meters, but I guess TDS-based instruments need to be more accurate because they are able to measure with a resolution of 1 ppm (the high-end instruments anyway) - and that's why they are expensive. Otherwise it's just a different scale as far as I know. Anyway - even TDS-meter aren't able to detect actual ppm of "listed" elements in a NS. They also measure the total dissolved solids - without distinction of their nature. In other words: part of the formula or not. Right, the TDS-meter like any EC-meter, can't do any distinction here. Perhaps someone who has more expertise with TDS-meters may confirm/correct or complement this part.

    Hope all is formulated intelligibly enough and not too complicated - after all I am not a native writer in english. Anyways, if anything remains unclear or if there are more questions, do not hesitate to ask!

    PS: Hope this isn't considered off topic either - well I am only answering a questions a bit too extensively (as usual I guess) ;-).

    Cheers,
    Lucas

  • grizzman
    14 years ago
    last modified: 9 years ago

    This guy does an excellent job of explaining how to calculate the the concentration of your nutrient solution. Be sure to follow some of the other links on the right side too as there is a lot of useful information there.

  • lucas_formulas
    14 years ago
    last modified: 9 years ago

    I guess I need to add something important here to avoid any misunderstandings:

    What I was explaining previously, wasn't about calculating the concentration of a nutrient as such. It is specifically about the difference between concentration in elements in a nutrient and the actual EC reading one has to expect. This is some very specific aspect and normally not part of any explanation about how to use formulas and calculus to get to a elemental concentration.

    By the way grizzman, I have a question to you here, as you recommend him: Does "This Guy" mention anything about this difference when taking an EC or TDS reading of a nutrient solution? I couldn't find anything about that part yet.

    Because I'd actually be glad to find a confirmation of my observations and the results of my testing somewhere.

  • grizzman
    14 years ago
    last modified: 9 years ago

    Daniel always proposed building your nutrient solution then taking an EC reading to develop a baseline from which to judge you concentration later based on the initial EC reading(i.e. the EC reading is a relative scale)
    As I recall, he basically said TDS is simply a conversion of EC numbers. At least that is how I remember it.
    you can see what he wrote yourself by searching for danielfp on this forum. Also, you can email him. he is a nice guy and replied to my emails when I sent them to him.
    I just say that because I don't want to incorrectly restate him as my understanding may be wrong or I am simply misunderstood him.

  • lucas_formulas
    14 years ago
    last modified: 9 years ago

    Right, from self-made nutrients you could always (and simply) compare the EC reading of your solution's outcome with the EC it is supposed to have in actual elements only. I pointed that out already. But to be able to do that, your concentrate MUST have an exact and known concentration, based on elemental content and Liter or Gallon. Otherwise you can't even tell what the actual elemental content of a ready solution is supposed to be. Having a precisely mixed concentrate is the condition, as you can't compare a known with an unknown.

    If you know the precise concentration, you don't even need a TDS- or EC-meter to mix your solution. In that case you'd know how many cubic centimeter per liter would equal the actual elemental ppm you are aiming for. Or in case you make it up for a thousand liter reservoir, you simply put all calculated ingredients in 1000 liter and that's it. You may do an EC reading of the reservoir's content to check or to know on what EC to lean to top up later. All actually depends on how you proceed.

    With commercial products, you even don't know what the elemental content is, as they don't tell you in the first place. That's why you can't compare it with the outcome of your EC-reading of the solution you'll use, until you ask them or determine it by yourself.

    With commercial products there is no problem as long as you use the recommendation based on quantity of concentrate/Liter(gallon). But as soon as you modify that concentration based on your own EC-reading, you aren't accurate anymore unless you know the difference of elemental vs. total ppm of your mix.

    EC-standard is actually a conversion of TDS. With TDS you measure directly the actual ppm units - while in EC-standard they get converted by multiplying them by 500 and divided again by 10. Hence 0.1 EC = 50 ppm, which isn't actually very precise after all. An EC-meter is in fact the poor man's TDS-meter. If you EC-meter would have a resolution/precision of two decimals, a reading of 0.01 EC would still equal 5 ppm.

  • lucas_formulas
    14 years ago
    last modified: 9 years ago

    Barely forgot to mention that all these calculus and formulas look terribly complex and complicated first. Once you are through with them and have them either on paper or filled in a spreadsheet, they become very obvious and self-explanatory.

    Looking at them during later practice becomes a routine like any other. For example: I've integrated the described comparison formula of elemental vs. total EC of a NS in my nutrient calculator. Now I am able to simply read both data in real time, as I modify any ingredient of a formula.

    Last but not least: people who are interested in modifying, calculating and/or making their (own) nutrients accurately, should truly consider investing (either work or money) in a decent piece of code. It considerably simplifies the thing!

  • grizzman
    14 years ago
    last modified: 9 years ago

    ACtually TDS is a conversion of EC. the meter actually measures the electrical conductivity of the water (in, I believe microsemens / cm). a TDS simply multiplies that by a constant (apparently 500 or 700) to give you a ppm measure.By multiplying a bumber to 10^2 you don't actually gain any accuracy.

  • greystoke
    14 years ago
    last modified: 9 years ago

    Lucas wrote:EC-standard is actually a conversion of TDS. With TDS you measure directly the actual ppm units - while in EC-standard they get converted by multiplying them by 500 and divided again by 10. Hence 0.1 EC = 50 ppm, which isn't actually very precise after all. An EC-meter is in fact the poor man's TDS-meter. If you EC-meter would have a resolution/precision of two decimals, a reading of 0.01 EC would still equal 5 ppm.

    It's actually the other way around. A tds-meter is primarely a conductivity meter measuring CF, or S (micro-Siemens). This reading is them mathematically converted to display tds (or ppm). The conversion factor is often adjustable to suit specific needs.

    The conductivty of dissolved salts can be calculated by using the limiting equivalent conductivity values for the constituent ions, which you can find in most inorganic chemical handbooks. The values are in µS per ppm per mol of the ion.
    In the case of CaCl2, you need to split the total ppm in ppm(Ca) and ppm(Cl). Then divide each value by the mol number (Ca=40.08, Cl=35.4), and then multiply with the relevant LEC value and add them together to get the final µS number
    LEC(Ca) = 59.5
    LEC(Cl) = 76.3

  • lucas_formulas
    14 years ago
    last modified: 9 years ago

    Grizzman, you are right about the measuring of electrical conductivity, that in fact gets converted to ppm with TDS-meters. You got a point here! But with what we call EC-meter there is a conversion as well. Here the electrical conductivity that the probe captures gets converted to millisimens/cm (which corresponds to 1.0 EC=500 ppm). What is actually captured by the probe needs to be converted into some standard, - otherwise, the displayed data couldn't be understood by the user. Hence the question of what is converted to what, only depends on, at what end of the equation you focus.

    The precision does obviously not depend or change with conversion , I didn't say or mean that either. The precision depends on the resolution of the probe and the chip in use in the instrument. Commonly used low price EC-meters, which should actually be called Millisimens-meters, to avoid any confusion of the sort, have only a resolution of 0.1 EC (probably with a precision of 0.1-0.2! Your reading may easily end up with variations of 50-100 ppm!

    I'll still call those the poor man's TDS-meter (as in having a resolution of either 10 or 1 ppm). Anyways, the reading of the display of a TDS-meter doesn't need to be converted to ppm, as it directly displays ppm.

  • lucas_formulas
    14 years ago
    last modified: 9 years ago

    @ greystroke, would you be so kind and use your nice "LEC formula" to calculate how much ppm 1gr of some components dissolved in 1 liter would read in Millisimens or ppm? Just for a few more components, - let's say: magnesium sulphate, potassium nitrate and calcium nitrate. Two of them would even be enough.

    I would be very interested in comparing the outcome with what I have got so far using rather Empirical means and methods.

    Thanks in advance!

  • greystoke
    14 years ago
    last modified: 9 years ago

    OK,
    MgSO4 1000ppm: Mg=24.31*1000/120.3= 202ppm; SO4=96*1000/120.3= 798ppm
    µS= (202/24.31)*53.1(LECMg)+(798/96)*80(LECSO4)=441+665=1106 µS or 1.1 EC (mS)

    KNO3 1000pm: 73.5(LECK)*1000/101.1 + 71.4(LECNO3)*1000/101.1 = 1433µS (Note: mol numbers cancel out!)

    Ca(NO3)2 1000ppm: 59.5(LECCa)*1000/164.08 +2*71.4*1000/164.08= 1233µS (Note: mol numbers cancel out!)

  • greystoke
    14 years ago
    last modified: 9 years ago

    There is no such thing as a TDS meter. There are only conductivity meters.

    When I was a young analyst, I was the "TDS" man. I used to weigh an empty 1L glass beker on an analytical balance, then filled it up with 1L of water, and left it in an oven at ±80°C, for 24-48 hours.
    Then I weighed the glass beker again, and voila your "TDS".

    A few years later the conductivity meters came along (and I lost my job LOL)

  • lucas_formulas
    14 years ago
    last modified: 9 years ago

    Here is what I have determined by measuring my components (1gr of the component dissolved in 1 Liter of water)

    Magnesium Sulphate 350 ppm (700 µS) - actual elemental content (considering purity) = 229 ppm
    Potassium Nitrate 675 ppm (1350 µS) - actual elemental content (c.p.) = 525 ppm
    Calcium Nitrate 487 ppm (975 µS) - actual elemental content (c.p.) = 341 ppm

    That's what I call the difference between theory and practice (at least in my case)!
    Only the KNO3 is "close" - and I am actually happy that I didn't rely on any theoretical knowledge here, but took the time to do it in an empirical way by measuring it old school. The reason for the difference is probably due to the fact that the formula doesn't consider fertilizer grade or purity (and whatever supplemental ions or "contaminants" each component may supply). And fertilizer grade is what is commonly the first choice, because higher grades are simply too expensive for the use. Measuring each component as it comes gives you ACTUAL and 100% reliable data. Though, measuring by hand and comparing your results with a formula aren't mutually exclusive. I would anyways warmly recommend to anyone who wants to have actual data for his own components, to at least confirm it through such simple empirical control tests.

    On the other hand, the actual nutrient formula based on ELEMENTAL ppm of each component can obviously only be calculated by the corresponding equations for each component,- unless you (are able to) make an analyses of each component and modify the values accordingly. In a normal case, you have to rely on the "popular" formulas and values in use (although considering elemental purity of each component - even with fertilizer grade, mostly as high as 97-99%).

  • greystoke
    14 years ago
    last modified: 9 years ago

    I'm not sure if I understand your explanantions. You said 1 gram in 1Litre. That's 1000ppm. Not so?
    However, if you include hydrates and impurities in the 1 gram, then - of course - we're no longer talking about one gram, but only a percentage of pure material.
    For instance, Epsom Salt contains 7 molecules of water. Therefor it contains a maximum of 49% of magnesium sulfate, which would equate to 490ppm, and ±540µS if 1gram was dissolved in 1L.

    I must admit that I don't know how to consolidate your values, but if you're happy with them, that's fine by me. I'm just afraid that they are dependent on the instrument you are using, or your interpretation of the displayed values (ppm vs µS), which makes them incompatible.
    The LEC system is not my invention. It's an accepted protocol. You can also find LEC values on the internet, and they're all the same. Some site even show you how to work with them

  • greystoke
    14 years ago
    last modified: 9 years ago

    I reread your post, and I think I understand what you're saying.
    I also buy fertiliser, such as: triple super-phosphate. I normally soak it in water to extract the calcium dihydroposphate.
    I then take a µS reading, and work back the PO4 concentration using LEC values. So that's a similar system.

    (However, I still can't figure out your ppm's LOL)

  • lucas_formulas
    14 years ago
    last modified: 9 years ago

    Well, I am sorry to tell you that you have either totally missed or avoided my real point all along, greystroke. You give a lot of input here, but nothing hits the nail even remotely on the head. How can that be?

    It is NOT at all about determining any elemental content in components or solutions!

    I am calculating my formulas in a very conventional and reliable way. I am using my own nutrient calculator. I can also cross-check the results with other nutrient calculators in case (which I frequently did until it was completed). So there is no doubt about the data I use and apply. Anyway, with a nutrient calculator there is no need to have a PhD in theoretical physics or chemistry anymore, to get it right. There is no need to do any supplementary measurements or tests either.

    What I was talking about here ALL ALONG, was the difference between actual elemental content in a nutrient solution (which is the result of standard formulas and values in use) and the final EC-reading of the same solution. Because there apparently (well actually) is a significant difference (10-15%).

    Please let's focus to finally get to a point here (figure of speech): have you ever calculated, weighted components and used your own formulas to actually make COMPLETE nutrients? Have you used a nutrient calculator, or have you cross-checked your results with one? If yes, have you ever compared the total elemental ppm that your solution is supposed to have (mathematically and by commonly used values for components), - with the actual and final EC-reading of that same solution? If yes, have you noticed any differences? If yes, how do you explain it?

    PS: is there anyone else who has insight here and is able to give some input about this end of the equation? Sorry to insist - No offense here: I mean THIS very end of the equation - Thanks!

  • greystoke
    14 years ago
    last modified: 9 years ago

    Lucas wrote:Please let's focus to finally get to a point here (figure of speech): have you ever calculated, weighted components and used your own formulas to actually make COMPLETE nutrients?
    We have more in common than you think. LOL

    Yes, I do make my own formulas from commercially available chemicals. I also make my own raw materials from wood ash.
    Yes, I use my spreadsheet calculator in which I have 46 formulas on file.
    Yes, I always test the purity of my raw materials by measuring their conductive strength of solution.
    and NO, I've NEVER found a discrepancy between the µS reading I finally got, and the one I should get (barring measurement errors).

    Before we go any further, I'd like to ask you a question.
    You confused me by not indicating that the 1 gram material was not pure material.

    (quote)Magnesium Sulphate 350 ppm (700 µS) - actual elemental content (considering purity) = 229 ppm
    The 1st question is:
    The 350ppm (700µS). . . is that what you measure when you dissolve 1 gram of your "MgSO4" in 1L of water?

    2nd question: What then is the "actual elemental content" of 229ppm?

    PS: I think we are badly off topic. We should start another subject.

  • lucas_formulas
    14 years ago
    last modified: 9 years ago

    Let's simply drop this, I guess it will not end up in anything conclusive for either of us and most probably even less for anyone else.

    Sorry, there is a sudden shift of priorities at this end.

  • greystoke
    14 years ago
    last modified: 9 years ago

    Fine by me, but I have a feeling that this subject will come up again soon.