wouldn't it be quicker to just provide n-p-k-mg-ca values versus doing screen shots?
i do direct addition so it is a bit easier versus making concentrates.
spurr,
Thanks for posting up more foo on custom mixing. I appreciate you putting it all into a post or two. Specifically the NPK and KCaMg ratios.
I should have read ahead before running my head in circles on the silicate. You might want to modify your provided instructions where you say to "add 10 ml per liter of final volume." It seems to be about 10X too high.
Spurr
Have you tried to formulate this on Hydrobuddy for a two part concentrate without the silica as I doubt that it can be added at that strength in a concentrate.
I can't seem to get Hydrobuddy to make a 500X concentrate. I want a gallon of part A and a gallon of Part B but no matter how I input it in Hydrobuddy it gets totally off the wall output. I do not mix and store diluted nutrients so I need a 2 part concentrate.
As usual I can not get Nutron2000 to formulate a mix with magnesium nitrate. I do not want to have to set Nutron200o locked at 132 ppm and then calculate manually to 140 ppm of nitrogen, then add the mag sulfate after calculating the magnesium contribution from the magnesium nitrate. I can deal with a larger nitrate and less ammonium content as it will be drain to waste. I can add the silo-tec to the water not the concentrate stock.
Have you played with the two part concentrate feature on Hydrobuddy yet?
Spurr wrote:
I was hired recently to create a few cannabis specific fertilizer formulations for various stages of growth, EC, source water, etc. Initially the person that hired me asked me to use Peter's Professional Hydro-Sol (5-11-26) as a base.
Below are some excerpts from something I wrote about this mix and making stock solutions in general, etc. I used HydroBuddy to make the following mix, and I am posting a version that assumes pure source water (i.e., doesn't account for ions as EC or elements, in the source water). I also didn't account for P from phosphoric acid, a common pH down product.
Below is a screen shot that lists the salt compounds used, not shown is 0.361 grams of boric acid into mix B. And how to mix bottles A, B and C. Use of A, B and C is 10 mL per liter of fertigation water, each.
The person that hired me grows in Sun Shine Mix #4 using drain-to-waste on a drip ring and timer; flushed weekly with plain water.
I.) Notes:
...
5) After messing around with lots of mixes, I found the perfect mix of inexpensive salts. The mix provides N-P-K of 3-1-4 and K-Ca-Mg of 3.2-1.84-1 [i.e., 4-3.2-1.25, what you requested]; as well as providing sufficient Si, NO3:NH4 ratio of 14, etc. The following are the salts I used, including those you don't yet have. Using the following salts, excluding the micro's, increase the accuracy of the ppm calculations a great deal, which is a very good thing. Using all of the following salts I was able to reduce the price per unit, too:
...
--> I attached two screen shots, the first one, "complete_mix_a", shows how to make the stock solutions (mixes) A, B and C. Ex., how much of each compound to add to each gallon to make stock solution (not shown is 0.361 grams of boric acid into mix B). That screen shot also shows the elemental profile by ppm, providing exactly what you asked for. The EC shown is 1.6 mS/cm, which is the EC of the fertagation water after the specified volumes of mix A, B and C are added. If we include the EC of your source water, i.e., 0.4 mS/cm, the total EC for your fertigtion tank will be 2.0 mS/cm; and I believe that is the EC you requested, correct?
II.) Mixing notes for stock solution:
a) when weighing dry salts use two scales: one that measures down to 0.001 gram and is accurate to 0.001 gram (jewelry scale for micro-nutrients), and one that measures to 1 kilogram and accurate to 0.01 gram, better yet 0.001 gram. Following is an example of en Ebay search for 0.001 gram scales: http://shop.ebay.com/items/?_nkw=sc...pt=1&_sadis=&LH_CAds=&clk_rvr_id=248929254212
b) when measuring liquid volume, ex., for Silo-Tec potassium silicate, use a good graduated cylinder, and a syringe for single mL and less than mL measurements. However, we can find the specific gravity of Silo-Tec and then use weight, instead of volume, to measure out Silo-Tec for mix C.
c) fill jug for mix A with 1/2 gallon distilled or deionized water, then add the salt compounds for mix A, shake and dissolve with each addition. Then add the other 1/2 gallon distilled or deionized water and shake.
d) do the same as above (re: mix A), when mixing B, and C.
III.) Mixing notes for fertigation tank (working solution):
a) fill tank to 1/2 volume with source water needed, ex., if you need 100 liter, fill with 50 liter.
b) add mix C (potassium silicate) at 10 mL per liter of total tank water and mix/agitate to fully dissolve (wait a couple of minutes), then adjust pH.
c) add mix A at 10 mL per liter of total tank water and mix/agitate to fully dissolve (wait a couple of minutes).
d) add mix B at 10 mL per liter of total tank water and mix/agitate to fully dissolve (wait a couple of minutes).
e) adjust pH
References:Daniel Fernandez wrote:
...
The buffers we are left with are then very simple organic and inorganic substances that have low phytotoxicity and some compatibility with the other ions present in our hydroponic setup. From these ions phosphate species, citrate species and carbonates are the most important ones we can use within our hydroponics setup. However we are limited by the actual concentration values of each we can use and for this reason we cannot have unlimited buffering capacity from these sources.
Which one is best? We can actually carry out simulations to show us the pH vs acid-base addition for different hydroponic solution constitutions using mathematical equations. Running these simulations requires the solution of highly complex systems of equations which contain all the information relative to the chemical equilibrium of all the different existing ionic species. The below shown simulations were carried out using the Mathematica computer program (all solutions are assumed to be adjusted to an initial pH of 5.8 with a strong acid or base).
The blue curve represents the behavior of a poorly buffered hydroponic solution with only about 0.002M phosphate concentration (about 50 ppm of P). The red and yellow curves represent two solutions with increasing levels of carbonate showing us that if you are battling pH increases, having more carbonate will definitely help you deal with this. However it is also clear that carbonate concentrations at pH 5.8 are restricted to around 100 ppm since values above this are bound to cause toxicity due to the very large presence of the hydrogen carbonate ion. The green curve represents an increase in the amount of phosphate from 0.002 to 0.004M (about 100 ppm) with carbonate, showing us that phosphates are not good at buffering increases towards the upper side but they do increase buffering towards acid territory. Overall I also noticed that citrate concentration increases to the maximum threshold allowed by calcium citrate solubility did not afford a very good buffering effect with only a mild effect that prevented shifts towards the downside.
In the end, the conclusion seems to be that in a regular hydroponics system where pH increases generally happen towards the upside it is better to use carbonate as a buffering agent than to use citrate or phosphate although phosphate at its regular concentration in hydroponic does provide some buffering against pH moves (without phosphate increases are much more dramatic). For this reason I believe that a phosphate/carbonate buffer seems to be the best choice for most hydroponic growers, taking care to keep the concentrations at levels that do not cause precipitation or phytotoxicity problems.