JZ's Shootout: Part Deux

[SteveHman]

No SteveHman, I am a sinner of the worst kind. I have no meters at all. I've been starting off with RODI, then adding 5ml/gallon of Cal-Mag. These were in 1/2 strength veg nutes, until I screwed the pooch and over nuted them.

I know also aeration of the reservoir tends to cause iron and calcium to precipitate out of solution, so that could be key too -- I wonder if coco coir with OC+, and just RODI might be the way to go with this set up. Lord knows it's been one failure after another, ever since I harvested the SAGE oh so long ago.

If you go with the OC+ I would use either straight tap water or half R/O and tap. Unless you add Ca/Mag to your res, but I wouldn't do that since Ca/Mag+ has nitrogen in it and I don't like to have nutes sit in a res that isn't aerated or circulating--unless you are using a zone type product.

 

[Jozo-sha]

That is all.



- JZ

 

[Bassman59]

Something tells me the next few days will be interesting as you get used to these.

Don't forget, find out what scale the tds meter is on so you can relate ppm based on the right scale.

Glad to see you got them.

 

[FrankFoster]

Once you have meter and do the base tests and your metric measuring from your tap water, then you barely need it. Say you have tap water at 7.8 that goes to 6.2 after nutes then 1 tsp per gallon of your ph down leaves you at 5.4-5.5. There is nothing changing your formula, and you won't need to check because you have your necessary system setup.

I used my ph,ec pen for many days at first, now I only take it out of the 7.0 packet when something seems questionable, and I can do 840-1100 ppm at 5.5 in my sleep. With 16 cc of gh triplicate.

But you are gonna be testing water like crazy soon.

 

[Jozo-sha]

The water out of my RODI is 0ppm - ergo no pH reading, however, adding 5ml/gallon of GH's CALiMAGic (much less N than Cal-Mag) gave this:

pH 5.8 @ 330ppm

Since the FloraNova Grow instructions recommend 600ppm for 'Most plants in early growth', would I go with that dosage, and shoot for a ppm of 900?

Inquiring minds NEED to know.

Oh, yeah, SteveHMan, my res is aerated, and quite well at that!


- JZ

 

[420GodsTrichome]

Have to let the hydro gurus chime in on this, hehe

 

[Mr. Krip]

The water out of my RODI is 0ppm - ergo no pH reading, however, adding 5ml/gallon of GH's CALiMAGic (much less N than Cal-Mag) gave this:

pH 5.8 @ 330ppm

Since the FloraNova Grow instructions recommend 600ppm for 'Most plants in early growth', would I go with that dosage, and shoot for a ppm of 900?

Inquiring minds NEED to know.

Oh, yeah, SteveHMan, my res is aerated, and quite well at that!


- JZ

Just to be clear, your RODI should give 0 PPM on the TDS meter, but should still register a PH value. Pure water has a PH of 7.

Now, when feeding your plants, you need to consider the TOTAL PPM of the nute solution, including the PPM's of all the nutes, supplements, PH adjuster, and the water itself. Using RODI, as you can see, the water should have close to 0 PPM, unlike tap or well water, etc. This lets you maximize PPM's of the nutes/supplements AND know exactly what's in the nute solution. For example, tap water may show 100 PPM, but you'll never know what makes up that 100 PPM without some detailed analysis.

So, if you're shooting for 600 PPM, you need to consider the Cal/Mag and have another 270PPM to play with.

But, your plants, depending on a bunch of factors, may be able to handle even more than 900 PPM. So, I would take a look at their current feeding schedule and up the total PPM's SLOWLY AND IN SMALL STEPS from there. Then, see how the plants react. If they start showing signs of burn, back it down a little.

5.8 PH is perfect for hydro, but remember that will change once you add the rest of your nutes, so you may need to re-adjust.

 

[Jozo-sha]

So - starting with RODI @ pH 7 and 0ppm, I added 5ml/gallon of CALiMAGic and 5ml/gallon of FloraNova Grow - the reservoir is full at 9 gallons, and my initial readings were:

pH 5.5 @ 770ppm

I added a mere 3ml of pH UP to the reservoir, and will retest the pH in about 30 or 40 minutes, goal of hitting a pH around 5.8 --




- JZ

 

[Vapedogg223]

So - starting with RODI @ pH 7 and 0ppm, I added 5ml/gallon of CALiMAGic and 5ml/gallon of FloraNova Grow - the reservoir is full at 9 gallons, and my initial readings were:

pH 5.5 @ 770ppm

I added a mere 3ml of pH UP to the reservoir, and will retest the pH in about 30 or 40 minutes, goal of hitting a pH around 5.8 --




- JZ

Now you see? They got you sounding more like a scientist than a farmer!

 

[Bassman59]

The water out of my RODI is 0ppm - ergo no pH reading, however, adding 5ml/gallon of GH's CALiMAGic (much less N than Cal-Mag) gave this:

pH 5.8 @ 330ppm

Since the FloraNova Grow instructions recommend 600ppm for 'Most plants in early growth', would I go with that dosage, and shoot for a ppm of 900?

Inquiring minds NEED to know.

Oh, yeah, SteveHMan, my res is aerated, and quite well at that!


- JZ

as previously mentioned you will still have a ph reading to check/adjust.

As for feed instructions, I was recently told by a 20 yr grower that runs over 76k watts over 3 locations, we feed our plants way too much.

His suggestion is on a .500 scale tds meter never more than 950 for the heaviest eaters. On a .700 scale he suggested never more than 1400ppm

on feeding he said: Your meter and your plants will tell you how high to nute. The way that you nute is that you draw a line in one of your buckets of where you keep the water level at. Anytime you take a reading, you must have the water filled to that line. What you want to see is that your plants eat 60 ppm over 3 days. For example if you put 600ppm of nutes in, you want the meter to read 540 in 3 days when you top off the buckets back to the line. If they ate more than 60 then yoir levels are too low. If they ate nothing and the reading is the same or higher then you are too high. Its that simple. You will find out that you were using twice the nutes that you needed.

 

[OG13]

As for feed instructions, I was recently told by a 20 yr grower
on feeding he said: Your meter and your plants will tell you how high to nute. The way that you nute is that you draw a line in one of your buckets of where you keep the water level at. Anytime you take a reading, you must have the water filled to that line. What you want to see is that your plants eat 60 ppm over 3 days. For example if you put 600ppm of nutes in, you want the meter to read 540 in 3 days when you top off the buckets back to the line. If they ate more than 60 then yoir levels are too low. If they ate nothing and the reading is the same or higher then you are too high. Its that simple. You will find out that you were using twice the nutes that you needed.

good advice on the line in the reservoir, but the numbers are moot. That is what works for his number of plants and res size. It will be different for everyone else. If you had a huge res, the plants couldn't eat 60 ppms that fast, but in a small res, they would eat way more.....When you have the experience, you will know how your setup works in that level of detail. It will take time an attention to detail.

 

[FrankFoster]

5.3-5.8 perfect... I would never add the ph up if I was even as low as 5.1.. Expecting the ph to rise in veg as the plant takes on the mobile elements. It's good the have the ph travel through the range of 5.2 to 6.5.... Then down again to 5.2 reset.

9 gallons is more than a simple 1-4 gallons so res changing costs$.

You could add more n in the triplicate nutes set knowing that you ppm % ratio is N p k, emphasizing n. and at 900 ppm you can know that with your npk won't get screwed up for at least 3-4 weeks. As long as the ph stays in range...

It's also easy to add the gh micro at 3cc per gallon every time you top off the tank. That's low enough not to add to you ppm and adds a bit of N p k every time the water level drops.

More ppm does not equal more yield.. As long as the soluble nute needed is there the plant can get it. And in fact the regulated auto ec auto ph auto nute systems run at 400-800 ppm 800 being almost too high. The advances in spectral nutes allow lower ppm and recently studies show that lower ppm on guided spectrums allows the plant to take in more water and puff up better.



It's only late when the ph drops as the plant eats away more p k.

In flower 9 gallons is great as you won't deplete the nutes daily, it might take two or three lol

 

[Jozo-sha]

Well, I'll check the pH again before I boogie to work - learning all this is great for my knowledge base, but the poor plants have to suffer.

The 4 little AF babies are sooo healthy and happy, I'm *almost* considering the pH'd RODI with ca-mg for coco in the reservoir, then just starting afresh with the 4 AF's in coir with OC+.

I loathe the idea of dicking with this and ending up with semi-cooked, half-ass flowered mutants that I created. I'm just trying to figure out how in the blue blazes I managed to get such a great harvest, sturdy plants from DWC, with just store-bought 'purified' water, FloraNova and no pH/TDS testing whatsoever.



- JZ

 

[sqwheels]

Hi JZ,

I haven't had time to post/read much lately...but had to reply on this subject, I agree with the need for TDS and pH meters...I only used a pH meter in the beginning but I feel the TDS meter gives me a better idea of what they are getting...thanks to 420fied I use the one that someone sent you a pic of...I think it was Mr.K.

for instance, when I make nutes for my hempy 2L's I do something like this...

start with RO/tap @ 60-80ppm, this way they get some Ca (and other stuff) that is naturally in my tap water, and this mix always has a pH around 7.0 - 7.1, then I add whatever nutes I'm going to feed that day (I have to water daily) almost always includes the GH floranova bloom that I'm currently using (I give just RO/tap every 4th or 5th day, depending on what the girls look like) I mix the RO/tap/bloom to 1000ppm (right now @ 20 days 12/12) this starts out about 300-400 when they are little and increases as they grow...I have found with my Wonder Woman they can take as much as 1300ppm late in flower stage before showing ill effects of nute burn.

I use 420fied's schedule for feeding and adjust to how the girls look...wk1-450ppm, wk2-700ppm, wk3-900ppm, wks4-10-1100-1400ppm.

Now...like Mr.K said...you take into account the total ppm's. when I add molasses to the mix I have to use a little less GH bloom or I'll go over the total ppm's I'm shooting for. I find 1 T/gal molasses adds about 100ppm to the total ppm's and raises the pH by .2, I'm sure you'll find your mixes to be a little different but after much testing and retesting you'll come to know what adds how much.

I only learned this with much help from others here @ 420mag and lots and lots of testing :icon_roll

for instance today I gave this...1/4 gal tap and 3/4 gal RO = 1 gal of RO/tap @ 62ppm/7.0pH, then I added 1-1/2t bloom to get 877ppm/5.4pH, then I added my molasses mix (3/4C RO/t heated to boil + 1T molasses) this gave me a total 987ppm/5.7pH...that's what I fed them today...tomorrow I'll do it all over again...because I mix my feed by the gallon, I'm not sure how this will differ from your res mixes but I'm sure it's gonna be something similar only on a bigger scale, maybe I'm doing this all wrong, I'm so new to growing that I probably shouldn't be giving anybody advice...but you asked and my girls are growing pretty good...although I think I still have my own issue with nutes/pH by the way they look...just keep experimenting, you'll get it

This was so long winded...I hope it helped.

Also, I don't know about the .500 or .700 scale on the TDS meter that Bassman was referring to...this is something I'll have to look into great...more research

BTW...If you have the time, come visit my journal...I have 1 each PE and OG kush x ultimate seedlings growing right now

 

[Bassman59]

Good stuff Sqwheels.

Yes I am happy I learned about the scale of the meter. I now understand it's importance. For example, your 1400ppm is probably good on a .7 (or .700) meter, but a large overfeed on say my .500 meter. And basically that really large grower was stating 95% of us overfeed even when we dont show signs of burn. So hey, now that I have saved you all a bunch of money, feel free to send me a small donation. Consider it "care for the elderly".

 

[sqwheels]

Bassman,

What's the difference and how do you know which you have?

 

[Bassman59]

Bassman,

What's the difference and how do you know which you have?

I guess it's the baseline of the readings taken on the meter. Or maybe put another way, x meter reads at 1.2volts while y meter reads at .75 volts. I know this isnt the proper way to say it, but hopefully you get the idea.

You should have some paperwork with the meter, or a website on the manufacturer that will give you the calibrated scale it's based on. That's how I found my info.

 

[Jozo-sha]

Mine says right on the front ".500"

 

[Bassman59]

Mine says right on the front ".500"

Cool, so now you know 1300ppm on that meter is hot. Where on a 700 meter it would not be so hot at 1300.

I'm not the one to make a call on where you should start or think about running at in various stages, but with the knowledge of your meter now, you should be able to gather the right info.

 

[Mr. Krip]

To add a little more clarity on this subject, EC is the measurement of the Electric Conductivity of the nutrient solution and is really the only true "universal" measurement of the strength of the nute solution. Electrical Conductivity is measured in siemens per centimeter (s/cm) or milliseimens per centimeter(ms/cm).

On the other hand, Total dissolved solids (TDS) is typically expressed in parts per million (ppm). It is a measurement of mass and determined by weighing (called a "gravimetric analysis"). A solution of nutrients dissolved in water at a strength of 700 ppm means that there are 700 milligrams if dissolved solids present for every liter of water. To accurately calculate total dissolved solids (TDS), one would evaporate a measured filtered sample to dryness, and weigh the residue. This type of measurement requires accurate liquid measurement, glassware, a drying oven, and a milligram balance. Example: 50 mL of the 700ppm solution would leave 35 mg of salt at the bottom of a crucible after drying.

Since a TDS meter can't do a gravimetric analysis, it instead uses a conversion factor to calculate it. Everyone’s nutrient mix is different, so no factor will be exact. The meter uses an approximate conversion factor, because the exact composition of the mix is not known. Conversion factors range from .50 to .72, depending on the meter's manufacturer.

PPM pens measure the value based on EC and then convert the EC value to display the ppm value, and, because there are different conversion factors between manufacturers, it creates challenges when communicating nutrient measurments to others.

There are actually THREE different conversion factors that meter manufacturers use to display ppm's:

USA 1 ms/cm (EC 1.0 or CF 10) = 500 ppm
European 1 ms/cm (EC 1.0 or CF 10) = 640 ppm
Australian 1 ms/cm (EC 1.0 or CF 10) = 700 ppm

Here's a chart that shows the different PPM readings at the same EC across different meter manufacturers:

So, when you're talking about PPM's, it's usually a good idea to also point out the conversion factor that's being used to calculate the PPM's. When you're talking about EC, there's no conversion factor involved..

I hope this helps!