So I’ve been looking into doing some hydroponics to not only grow some tasty vegetables but to increase the growing season in my area. I’ve found a number of helpful sites that talk about what you should do and how you can do it, but one particular item is always missing: They specify what the various nutrients and amounts of such in the water should be, but in order to get an accurate count, you have to send off a sample to a lab.
I would really love to be able to do that analysis myself, saving on both time and cost, so I am looking for ideas / chemistry that would help me analyze the contents of the nutrients in the water. I know some of the people of the board here do this professionally, and I am curious as to the process used to get the results, and most specifically if I can do / build something that would help me do this quickly and perhaps even cheaply.
Here are the items I am looking to test for, along with their quantities in parts per million (PPM):
Liquid samples containing ppm levels of metal ions are typically analyzed via Atomic absorption spectroscopy or x-ray fluorescence. The machines are pricey and can be cranky, so even if you find a heck of a deal on ebay, you might not be able to routinely get the results you require.
Doesn’t someone already sell a macro/micro nutrient ready-mix that you can just dilute to the strength you want?
WAG Get a pre WWII A.C.Gilbert Chemistry Set off of e-bay.
Realistically you will have to acquire the skills of an analytical chemist or find some good ‘cookbook’ analysis procedures applicabale to the elements you listede. In addition you will need lab equipment, glassware, and reagents.
Semms like you are embarking on a program of overkill!
Do all the hydrophonic ‘farms’ do this much detailed analysis?
Just do trial and error. Set up one tank for every possible combination of nutrient concentrations, and see which one works better. A small continent should provide enough room.
The list I posted earlier was from chapter five in that link.
Great! I’ll take a look there. Spectroscopy is something I would love to try to do on an amateur level, although I think I will leave the X-rays alone… neighbors tend to complain, ya know…
Yeah, it seems a lot of people have such a mix, and this is certainly the way most people do this, but I would love to have any excuse to really get into the whole science of the thing. I would also like to be as self sufficient in my operation as possible without having to rely upon a pre-made mixture available from Company ACME. I figure that if they can make the mix, I ought to be able to do the same. This is kind of an experiment in self reliance as much as it is about growing stuff.
I would be surprised if they did this much analysis in the large majority. I’m sure most of them just add nutrients on a schedule or when they see a problem crop up indicative of a lack of a certain nutrient.
I am always willing the acquire the skills of an analytical chemist, but I am hoping to only have to learn the skills specific to the processes needed to identify the specific elements listed above. Any ideas where I can find a ‘cookbook’ of those procedures? Or are these industry secrets only shared among a select cabal of labs?
You can do these with basic wet chemistry, although it can get a little complex and the reagents, glassware, scales, and pipettes will set you back.
These are metals… you need all the stuff I mentioned above to digest the sample, and then you need an AA or ICP to analyze (and these aren’t cheap). Accurate metals analysis can be expensive.
You can send them off to a lab… IIRC each one of these tests can go in the general ballpark of $50 each, plus sampling costs.
A quick search of the Hach website shows that they have test strips, and I suppose other suppliers do as well, that will allow you to affordably test for Nitrate, Ammonia and Phosphorus.
The rest of you parameters look like they would be expensive to do at home. But if you are interested I would suggest the book “Standard Methods for the Examination of Water and Wastewater” 18th or 19th Ed.
As for lab prices, well I only have access to my lab’s price list. We charge $10 per element for ICP plus $12 to prep the sample. So for your list of metals (K, Ca, Mg, Fe, B, Mn, Zn, Mo, Cu) it would run $102 per sample. The nutrients would run $15 each (NO3, NH3 and P). We don’t have a price for Sulfur, but I would guess that it would be around $25.
Setting up your own lab could be a lot of fun, but it might not be cheap. It might be more economical to send them to a lab.