Spurr's groundbreaking fert. mixes and methods (YouTube screen-cast and web site!)

[spurr]

Hey Spurr
I could use a little clarification re: alkalinity buffering. Looking at the article from D. Fernadez that you linked http://scienceinhydroponics.com/200...your-hydroponic-nutrient-solution-stable.html

It appears from the graph that the carbonate provides buffering "towards basic pH values" (yellow line); however in your text concerning the addition of K2CO3 (in your writing about Brun-Water) you state it's purpose is to "hinder acidic pH swings", and citric acid is used because it is a "good buffer to higher basic pH swings"...however, comparing the blue line (citric acid alone) and yellow in the graph shows that the carbonate/citric acid combination is better to prevent swings upward in pH, suggesting that the alkalinity contributed from the carbonate is what is buffering the pH from rising. Any insight you can provide here is appreciated, as my problem is chasing an ever rising pH, and I'm trying to determine if re-mineralizing my RO water will help matters.

Daniel was referring to carbonate buffering against pH drops, i.e., it buffers "toward" basic pH value. And the opposite is true for citric acid. You could post a message to Daniel on his blog to make sure I'm correct in how I am representing his claims, but sadly he told me he's not responding to anyone any longer re HydroBuddy, and he's not working anymore on Hydrbuddy until next summer, if even then.

When you use citrate (citric acid) and carbonate as a pH buffering "system" they work in a synergistic fashion. Alkalinity (can strongly) increase pH if it's much over 100 ppm, esp. if the alkalinity starts low*, it doesn't buffer against increasing pH, it buffers against decreasing pH.

* To find the increase in pH from X ppm alkalinity (as HCO3 or CaCO3) addition to Y ppm alkalinity in staring solution use the following equation. Any scientific calculator can do this math easily, just press the "log" button, enter the ppm values with a divisor "/" between them, and then press the ")" button; finally press "ENTER". I use a Texas Instrument "TI-83 Plus" scientific calculator:

log(starting alkalinity ppm/final alkalinity ppm)
​

Also, can you give more detail about how the addition of 0.096 g/L of K2CO3 results in the 71ppm of CaCO3? What would be the equivalent calculation if using CaCO3 to provide alkalinity?

thanks for the great information and thread

I assume 5 ppm CaCO3 in RO water because according to Bill Agro(sp?) average CaCO3 for RO water is < 10 ppm. Then I add the 71 ppm CaCO3 contributed from 0.096 g/L K2CO3, for a total of 76 ppm CaCO3. I will have to get back to you on the math for using CaCO3 instead of K2CO3, you would use close to the same quantity as K2CO3 fwiw ...

 

[Rukind]

You don't have to use AquaGro L PsiMatric, it's merely just what I plan to use and it's the professional gold standard, AFAIK. "Soax" is another top tier professional NIS. I would suggest AquaGro L PsiMatric is #1, AquaGro 2000-L is #2 and Soax is #3. Candaian's cannot buy AquaGro L PsiMatric from Canada, but they can buy AquaGro 2000-L or Soax from Canada.

The shitty part is AquaGro L PsiMatric only sold by the gallon, and it's ~$100 for a gallon. AquaGro 2000-L is a bit more expensive and less concentrated vs AquaGro L PsiMatric. I asked AquaTrols to being selling AquaGro by the liter (or quart) and they told me they will ask their sales director if that possible in the future.

AquaGro L with PsiMatric Techonology:
(1 gal = ~$100)
http://www.hummert.com/ProductImages/10-2800.jpg

​

Berger BM6:
(~$35 for 3.8 cubic foot compressed bale at 2:1 compression ratio; or ~$16 for 3.0 cubic foot 'loose fill' bag)
http://www.jrjohnson.com/product.php?productid=16151&cat=348&page=1

​

Parboiled Rice Hulls ("PBH"):
(4 cubic foot compressed bale is ~$10. I use for mulch, I tested analytically as media amendment with s.peat base and I didn't like results wrt air porosity and esp. water-holding capacity)
http://www.hummert.com/ProductDetai...chList.aspx&ID=9062&Text=parboiled rice hulls

​

See what DonkDBZ wrote: check out Ebay or on-line stores. If you are using UNH AlkCalc yourself, and not relying upon my default values, then you can use any purity acid you find offered by UNH AlkCalc. I.e,. phosphoric acid at 75% or 85% purity and sulfuric acid at 35%, 50%, 66% or 96% purity.

If you find an odd (uncommon) purity of either (or both) of those acids, that is higher than what I used in my methodology, use the math I posted a few pages back to dilute your acid to purity values offered by UNH AlkCalc or my default purity values.



I would go with Berger Bm6 if I were you, or Berger BM4 and add your own aeration amendments like calcined DE. However, that means you have to order them. And I'm not sure if you do so, but reusing soilless media (i.e., no till) is a way to save lots of cash from grow to grow.

Sunshine #4 works very well, it was my go to retail soilless media for a long time, when I didn't make my own soilless media. It's good stuff.

I am not a fan of coco, but many people have great success with it, like YS. Those pics he posted on the last page were grown in coco .

FWIW, here are some tips on proper media handling wrt porosity:

If air porosity of media is 20% (a good value; water-filled porosity should be 55-65%) when seed or clone is planted, the air porosity (most often) should increase to > 20% once roots start to fill the media. That is, if proper watering technique is used. Also, make sure to pre-wet the media (coco or s.peat) before adding it to container. You should moisten it, then let it sit awhile, then fill container. And try not to move containers once they are full. Finally, use media depth of at least 10", if possible, the reasons are two fold: (1) to reduce the "Perched Water Table" (and thus increase air porosity); and (2) because roots have high rate of activity (water and ion uptake) at 10-12" depth (I will use 16" deep x 12" wide x 7' long beds of BM6 next soilless grow).




If would start off with one tensiometer because 3 gallon pots are not overly deep and to save some cash at first (they are ~$100 a piece and you need at least one 'service' kit for ~$50). Two tensiometers (one shallow and one deep) may not work well in one container.

Place the tensiometer in the media while you're filling the container, and leave it in media all the time. Place the tensiometer at the direst area of media, e.g., if using drip emitter place it from 90 to 180 degrees from the emitters. I would place the ceramic tip between 4-6", considering 3 gallon pots aren't deep and we don't want the tip to be below the Perched Water Table. How deep are your pots?

You can use one tensiometer for a few different strains (i.e., unique plants) of the same cultivar (e.g,. NL #5), or different cultivars (e.g., NL #5 and Skunk #1). However, the catch is the strains all should very similar water use rates. Most often they do not, even strains from the same cultivar. If you're using one tensiometer for say 20 plants (i.e., strains) of the same cultivar, make sure to try and provide as uniform environment (root and shoot) as possible for all plants, that way water use rate is more uniform.



Yes, ProMix HP is fine, it works well. I would use full strength then dilute strength (e.g., 30% or 40% depending upon how often you irrigate), then full strength, then dilute strength, and so on. That is, if you're using soiless media without organic fertilizer inputs. Ocean Forest is soilless but it also has quite a bit of organic fertilizer inputs, IIRC.

It's best to not drop severely EC between waterings if possible, it's better to keep osmotic pressures (re EC) fairly consistent all the time. Using fertilizer solution then plain water then fertilizer solution, then plain water, and so on, in non-amended soilless media is not ideal for roots. It would be better to make an "isotonic" solution and use that instead of plain water, if you don't want to use fertilizer solution every watering; or buy isotonic solution such as the myriad of 'flushing' agents that use sugar. Daniel wrote a good blog post about how to easily make your own isotonic solution, then you don't have to buy shit like "Final Flush", "ClearX", etc.

Making Isotonic Solutions For Draining : Preparing Your Own – and better – Clearex
http://scienceinhydroponics.com/201...ng-preparing-your-own-and-better-clearex.html

​

Good idea, don't trust them. If you flush it, then let it dry out a bit to near field capacity (aka container capacity), so it's moist but not wet (only one or two drops of H20 should fall from hand with 'squeeze test'). Then fill containers when moist.



For good brands you can just flush with RO water, which is acidic anyway (but sulfuric acid won't hurt, just more work, and I wouldn't drop pH below 4.5). Test EC when you begin to flush and let it drop down below ~0.2-0.4 if possible.

It's best to wet media, then wait a little while for water to fully hydrate media, then flush.

I will probably go with pro mix hp because my hydro store only has sunshine mix #4 "advanced". It has coco in it as well. I dont feel good about ordering my media, maybe when it gets warmer and lots of people around here are planting outdoors.

I watched the berger video's you posted and it was helpful. I never did my soil right. I always just put it in the bucket and then watered. I am familiar with field capacity so it shouldn't be a problem anymore.

I will look around ebay some more. Maybe I will just order the 85% and just use it to bring my ph down to 6 (after the potassium carbonate, protekt, citric acid) since I do not have a tds meter. Also, I am considering getting some hydroplex if I dont want to get phosphorus from ebay. I know it has potassium in it too and it would be more beneficial to add more phosphorus and not potassium in full flower. If i were to use hydroplex, I would only use it to bring down the ph to 6 after I add potassium carbonate, pro tekt, and citric acid. only in full flower of course. If it doesn't lower the ph to 6 after I add about 2.5ml/gallon of hydroplex, then I will add more citric acid to bring it down to 6.

I have a lot of clearex to use so I mite put it to use like you recommended. I had no idea that stuff was just sugar lol I wont be using ocean forest, i am going with pro mix hp i think. When I used ocean forest, I didn't even feed for about 3 weeks to a month. Plants always looked healthy for about 3 weeks and then they would start to show signs of deficiency. that is when I would start feeding.

Since I have a lot of clearex, would this be okay or close to the same EC:

potassium carbonate
protekt
citric acid
(the above is the usual to get a ph of 6 and help balance the ph of the media. I figure you should always give the plants this until the last week before harvest.)

10ml a gallon of clearex

I am not sure how much clearex to use per gallon to match the EC of your nutrient solution. I always just used 10ml like it says on the bottle. I think it says between 7 and 15ml per gallon or something like that.

 

[YosemiteSam]

For the record some of those plants are coco and the rest are 50% peat, 25% perlite and 25% some combo of local thermal compost and ewc. The peat plants were amended with chicken shit, bone meal and gypsum...and watered. The coco plants were fed chem nutes.

The healthiest plants were in the peat...highest brix readings (refractometer). Taste tests will soon begin.

For me it all comes down to which you are best able to control root zone pH with, with no added pH down. For me it is about matching the media to my water source. The peat/gypsum (no limestone) proved to be the winning formula for my water.

For me the most important thing about peat is the microbiology...which one has the most. For me that is Alaska peat.

Yo is in the process of going organic indoors.

 

[spurr]

For the record some of those plants are coco and the rest are 50% peat, 25% perlite and 25% some combo of local thermal compost and ewc. The peat plants were amended with chicken shit, bone meal and gypsum...and watered. The coco plants were fed chem nutes.

The healthiest plants were in the peat...highest brix readings (refractometer). Taste tests will soon begin.

For me it all comes down to which you are best able to control root zone pH with, with no added pH down. For me it is about matching the media to my water source. The peat/gypsum (no limestone) proved to be the winning formula for my water.

Church

Is the refractometer temp compensating?

For me the most important thing about peat is the microbiology...which one has the most. For me that is Alaska peat.

I read you posted something similar at GardenSec I think. FWIW, there is no "Alaska peat" or "Alaskan peat" on the the market AFAIK. I believe you're referring to "Alaskan humus", e.g., "Danila Gold" brand.

It's best to add biota pretty often, via Aerated Compost Tea (ACT) and Non-Aerated Compost Tea (NCT). Some people use the term "AACT" (Actively Aerated Compost Tea) but that's a bunch of bullshit branding by the so-called doctor Elaine Ingham (she's a moron and liar).

Foliar application of those microbial solutions is very beneficial, more so with NCT than ACT, to apply biota to the "phyllosphere" (re disease inhibition and growth benefits).

Also, if you have issues with PM one of the best organic methods to prevent and fight back against PM is using a mixture of skim milk and whey as foliar spray. But it must be sprayed in the morning or when lights turn on to 'work'. And if you include horsetail extract, IIRC, it's even better against PM (that's a tip from jaykush). Inluding Si in a foliar spay with milk, whey and horsetail extract makes about the best PM spray one can use short using harsh fungicides and fungistats. White mineral oil is also organic and useful against PM, e.g,. JMS Stylet Oil brand.

When using biological organic horticulture (not 'organics in a bottle'), it's the microbes that carry out "nutrient cycling" and "mineralization" (of OM and microbes) via interactions of "soil food web". As well as fixing N2 from air into bacteria 'bodies' which are then 'eaten' during the process of predation (re nutrient cycling).

It's wise and beneficial include some biological organic horticultural practices (such as ACT and NCT) with conventional horticulture (use of fertilizer compounds), for the best plants vs just conventional horticulture. The world's biggest pumpkins are grown that way, fwiw .

Yo is in the process of going organic indoors.

Then you're talking to about the best source possible, yours truly , as well as Microbeman, CTGuy, JayKush, VerdantGreen, Vonfron, mad librettist, MrFista, and others in the organic soil sub-forum. This web site is far beyond all other wrt biological organics, esp. the OFC. There is no other place on the whole Internet (AFAIK) wrt cannabis with more correct info and greater knowledgeable people than here. Hell, just having MicrobeMan here alone makes this site better than all other cannabis sites combined times 10 wrt biological organics.

If you'd like I will nominate you to join the Organic Fanatics Collective (OFC), it's a social group run by JayKush here at ICmag. It's better quality info and more of it, with much higher signal:noise ratio vs the organic soil sub-forum. If you're into microbes you really should join the OFC.

FWIW,
The whole reason I made my formulations and studied these topis so thoroughly was to create ideal, scientifically sound cannabis specific nutrient formulations so I can carry out advanced studies comparing growing cannabis using conventional horticultural vs biological organic horticulture, my true passion and love.

 

[spurr]

@ YS,

Oh yea, MicrobeMan carried out microbial assays on ACT he made using only Premiere peat as the microbial input (i.e., source of microbes) via "direct microscopic enumeration" (DME). DME is method we microbe nuts use with our microscopes we bought from MicrobeMan to assay our media extracts (i.e., soilless solution) and microbial extracts (ACT and NCT, even LCT) for mesofauna (nematodes), microfauna (protozoa) and microflora (fungi, bacteria and archea).

MicrobeMan found high counts of fungi from Premiere, and decent numbers of bacteria too (IIRC). He was happy with Premier wrt indigenous bioita. That means if we use Premiere peat as a base we are starting with a good base of biota.

Berger peat moss also carries out microbial assays for each batch of s.peat. However, I'm unsure if they use DME, "most probable number" or plate counts; the latter is the worst option. You can contact them to get the results, IIRC.

 

[spurr]

@ YS,

FWIW,
A majority of the N ionic species in rhizosphere and soilless solution from microbial predation, i.e., nutrient cycling, is in the form of NO3.

P.S.
I think I've gotten the word out far enough so most people now know it's fact we can't mix AM fungi (e.g., Glomus mossaea, and other Glomus species such as G.intraradices) with P much over ~20 ppm. That is, if we anything resembling sufficient infection of host roots by AM fungi, and feeding of AM fungi by roots as well as AM fungi health, sporulation and growth of "mycrosphere" (into "bulk media"). Not only that, but it's best to NOT use a freeze dried spore mix of AM fungi and trichoderma, because the trich spores will germinate first and pray upon some of the AM fungi spores and young fungi. In fact, it's best to NOT use freeze dried AM fungi spores for various reasons such as time to sufficient infection of host roots (weeks/month(s)) and viability of most spores.

The topic of how to properly use AM fungi is something I have written a lot about, for quite a while. For a long time I was the lone voice against the bullshit madness and myths about AM fungi coming from the cannabis world. I cannot wait for the day we have killed all those fucking myths!

 

[DonkDBZ]

The B stock solution will not work. The Magnesium sulphate causes the di-ammonium to fallout. Mixxed in a couple different orders no go.

 

[spurr]

What temp was water? And was it distilled or deionized water? I know that screenshot lists them as not mixing, but they should, ex., GH Grow has ammonium phosphate and magnesium sulfate.

 

[DonkDBZ]

round 78 degree. it was 5ppm RO water.

I mixxed everything but the dap and copper sulphate. add the dap and mixxed fellout. I then mixxed dap by itself looks good. then mixxed in the mg sulphate and within 30 secs a white powder forms and falls to the bottom.

amounts were round 90grams mg suphate and 15dap into 750ml water

Mixxed a batch of A 5 days ago and it looks great.

Grow also shows magnesium carbonate and potassium carbonate which according to hydrobuddy cannot be used in solutions. There bloom says magnesium phosphate but I cannot find specs for that. They could put stop on the label just to throw people off and may not be in there at all. Look at old big bud powder shows 7% mg but lab tests showed less then 1%

Cutting edge grow, same numbers just a few ingredients.

I will just make a A-ag-sil,B,C,D-dap

 

[spurr]

Sure that works to make an extra stock solution, however, that shouldn't be needed. You should be able to mix them. I'll test it very soon at that temp using RO water to see if I get the same result.

For stock solutions don't use RO water. Use at least distilled water and temp of at least 90'F helps a lot. Cool water isn't helpful.

Also, how did you mix them? Did you use 50% volume of total water volume (e.g., 1/2 gallon for 1 gallon stock solution) when mixing salts as I wrote about? And then measure water volume after adding salts and subtract that volume from the total volume, for the resulting volume to add to reach the total volume (e.g., 1 gallon)?

And did you wait for each compound to fully dissolve before adding the next? Sorry, I know you prob. did all this, I'm just trying to cover all bases ...

FWIW, HydroBuddy lists DAP (as well as MAP) and MgSO4 as stock solution B.

 

[DonkDBZ]

I used the amount for 45gallon direct add. put around 900ml water. added and dissolved each fert one by one added. I was not overly concerned by end amount cause I will just dump the whole container into my 50 gallon res.

I normally use distilled but I am just making test batches for fallout test.

The part A that looked great after 5 days was 375 concentration (10ml/gallon)

Busy for next couple of days so sunday I will play around some more

I have some haifa MAP too I will see if it does the same shit

 

[spurr]

Hey,

I think I may have figured out what's going on: pH. What is the pH of you water? Lower pH allows salts that otherwise can't be used together to be used together in the same stock, ex., CaNO3 and MAP, CaNO3 and DAP, CaNO3 and MKP (when P isn't very high).

Understanding Plant Nutrition: Fertilizers And Macronutrients
Argo and Fisher take a microscope to the details that can help growers make informed decisions on nutrients.
By Bill Argo and Paul Fisher (August 2008)
http://www.greenhousegrower.com/magazine/?storyid=1158​

Ex., GH Grow has a pH of ~4 to ~4.15, thus ammonium phosphate and MgSO4 can be used, the lower the P the better wrt mixing. Likewise, other stock solutions where incompatible salts (cations and anions) are mixed (like 'one part' fertilizers) use a low pH to accomplish the mixing. That is why citric acid is in FloraNova, so incompatible salts can be used in the same stock solution. Check the pH of FloraNova, I bet it's < 4.5.

Try lowering the pH of stock B with citric acid to pH 4, then mix the salts. That should fix the issue. Also use warm, or better yet, hot water. And use distilled water, as you normally do.

 

[DonkDBZ]

nice will try. room temp water was also part of my test of the chart in post #111

 

[Rukind]

is it okay to pre mix a solution of just ro water+potassium carbonate and another solution of ro water+citric acid. Like 500ml of each? That way I can mix those 2 up once a month instead of every time I water. I was just wondering how long they would last in ro water before they wont work anymore?

For example, I would like to pre mix potassium carbonate, citric acid, and epsom salt in their own seperate containers so I can use over and over.

Container 1: dissolve 18.15 grams of potassium cabronate into 500ml of ro water. this would provide about .363g of potassium carbonate in 10ml of ro water. 363mg should be accurate enough for a gallon of water.

Container 2: dissolve about 5 grams of citric acid into 500ml of ro water. this would be about 100mg/10ml per gallon of water more or less depending on ph. I know this isn't exactly right, but I would use this to adjust ph, so at this point in time, it doesn't have to be completely accurate. I will be using your gh formula until you release your nutrient line or I get better equipment.

Container 3: dissolve 25 grams of epsom salt into 500ml of ro water. this would make it .5g/10ml per gallon

My math could be wrong I am tired right now. I am just wanting a long term storage (about a month or 2) of these pre mix solutions. It would make things a lot easier.

 

[YosemiteSam]

Actually I can pick up Premier Brand at nurseries here...a lot less shady than hydro stores. Then local compost, ewc and some perlite and I would be good to go.

For me, the choice of coco or peat comes down to which works best with ones water. Currently I am guessing peat is the answer for me.

You know I believe in low P anyways so that won't be a problem.

The question for me is how to add enough food so that by the end it is running low near the end. Ideally I would like to find something that pretty much totally runs out by the end of the cycle...then lets me re amend with the same amounts for the next go round.

As far as teas...well I believe if you get the C:N ratio right in the first place you are better off letting the soil work than handing it all kinds of shit whether it is beneficial or not, ala Tom Hill. But that would be open for testing.

And I agree...no finer forum for organic.

edit...my refractometer is the one from Peaceful Valley Farms. It is not temp compensating. But you calibrate it every use with distilled water...so if that is the temp of the sap it should be ok. Plus, absolute accuracy is not as important in this case as watching trend lines.

 

[spurr]

The question for me is how to add enough food so that by the end it is running low near the end. Ideally I would like to find something that pretty much totally runs out by the end of the cycle...then lets me re amend with the same amounts for the next go round.

This isn't the correct thread for such discussion, but I'm happy to help you via PM or via threads in the organic soil section. For now, with biological organics we are much less in control, it's (mostly) up to the plant and the microbes. They communicate with each other, in a fashion. There is no reason to try let 'food run low' at the tend with biological organics. And you shouldn't try to rely on only OM (Organic Matter) to 'feed' you plants. Sure, OM is good for P, K, Ca, etc., but microbes are needed to "mineralize" the OM (for the most part) so plants can use the ions (or DON and DOP, as the case may be). In fact, microbes will be giving 'food' to plants all time, even more so when the plant gives/communicates with biota (esp. in rhizosphere) via exudates.

As far as teas...well I believe if you get the C:N ratio right in the first place you are better off letting the soil work than handing it all kinds of shit whether it is beneficial or not, ala Tom Hill. But that would be open for testing.

It has very little to do with C:N. Btw, ideal C:N for soil and soilless is ~9-11. Please don't listen to Tom Hill, he lacks critical understanding of the issues he thinks he has mastered. He has been eviscerated by much more experienced and knowledgeable folks, such as MicrobeMan, JayKush(IIRC), myself, and others in the past.

To build a good media you only need add OM to a s.peast base, such as soft-rock phosphate, calcidic lime and dolomite lime, Azmoite, zeolite (for amorphous silicate, aka amorphous aluminosilicate), calcined DE (please don't use perlite), and good vermicompost. Some people also add things like a bit of alfalfa meal, rice meal, guano, etc. (I am not a fan of guano). Just keep in mind we are trying to make an ideal 'home' for microbes, and let them do all the 'heavy lifting'. Do not rely on OM inputs to 'feed' the plants ...

FWIW,
Homemade, or otherwise 'good' vermicompost (that's not the same thing as vermicast) is better than most thermal compost because most thermal compost sucks ass (wrt C:N raito, humus, humic fraction, nutrients, etc.). I can help you find great thermal compost (al a' Luebke Compost, ex., from here). Or I can teach you how to make the best thermal compost, using my methods and spreadsheet calculator I have developed over the past years using science from Cornell, Rodale, Penn State, WA State U, etc. In fact, search the organic soil forum with my username and the term "Luebke", as well as "fleece".

In short: Making good compost isn't as easy as mixing "green" with "brown", one must account for moisture content, particle size, air porosity, water-filled porosity, bulk density, C:N ratio, C ratio, lignin, cellulose and hemicellulose, calcium, nitrogen "volatilization", mechanical turning or forced air, core temp (re: microbes that are mesophiles, thermophiles and hyperthermophiles), etc, etc. My method makes for better compost than Luebke's method, i.e., "Controlled Microbial Composting", and Luebke's method is one of the best in the world.

edit...my refractometer is the one from Peaceful Valley Farms. It is not temp compensating. But you calibrate it every use with distilled water...so if that is the temp of the sap it should be ok. Plus, absolute accuracy is not as important in this case as watching trend lines.

Sounds fair. FWIW, do you know about a guy called NCGA? He's a big time outdoor grower in Cali, and quite famous. He and I are on-line buddies, he posts over at TCC. He has been using refractometers (as well as Cardy N and K ion-selective electrodes for leaf sap testing) for many years, over a decade. He has vast reams of the data you are referring to, re trend lines. He is of the opinion that Brix score is of little use to growing cannabis. I can get you in contact with him, if you wish.

 

[spurr]

is it okay to pre mix a solution of just ro water+potassium carbonate and another solution of ro water+citric acid. Like 500ml of each? That way I can mix those 2 up once a month instead of every time I water. I was just wondering how long they would last in ro water before they wont work anymore?

For example, I would like to pre mix potassium carbonate, citric acid, and epsom salt in their own seperate containers so I can use over and over.

Sure. However, a little math would be involved, e.g., specific gravity and such. Why do you wish to per-dissovle MgSO4?

My math could be wrong I am tired right now. I am just wanting a long term storage (about a month or 2) of these pre mix solutions. It would make things a lot easier.

I can work out the math to check yours later, I'm short on time now. But you logic seems sound.

 

[Rukind]

Sure. However, a little math would be involved, e.g., specific gravity and such. Why do you wish to per-dissovle MgSO4?



I can work out the math to check yours later, I'm short on time now. But you logic seems sound.

The reason i wanted to pre dissolve epsom salt is i remember reading a post of yours before this thread about pre dissolving epsom salt in some warm water first.

I used to just drop .5 grams straight into my nutrient solution instead of pre-dissolving it first. so pre-dissolving magnesium sulfate isn't necessary?

 

[spurr]

Nope, you don't need to. However, MgSO4 can be a bitch to quickly and fully dissolve in cool water. So it can be helpful, for sure. I only wrote that K2CO3 and citric acid should be pre-dissolved. However, you don't have to pre-dissolve the base and acid, if you don't wish to do so.

 

[Rukind]

Nope, you don't need to. However, MgSO4 can be a bitch to quickly and fully dissolve in cool water. So it can be helpful, for sure. I only wrote that K2CO3 and citric acid should be pre-dissolved. However, you don't have to pre-dissolve the base and acid, if you don't wish to do so.

Alright, thanks again.