Grow Mediums Cal Mag ? or PH Osmosis Stabiliser ?

[true]

Hi All,

See below an email from me to House & Garden USA.
I'd be interested to hear your thoughts on this.


-------------------------------------------------------------------------------------

You will want to use PH Osmosis Stabilizer in this situation. There is PH instability that is associated with zero and low PPM water and this product will help to basically re-mineralize your RO water.

Cal Mag products are used by gardeners with RO water as a "band aid" type of fix to address this PH instability. PH Stabilizer will help to keep your PH more stable for up to 10 days where a cal mag product might only help stability for 2-3 days or less.

A cal mag product might be needed as an actual cal mag supplement, it really depends on the genetics you are working with. For the most part though, Aqua Flakes has a fair amount of cal/mag already in it and may not need more. Calcium toxicity is something to watch for if adding additional calcium. I definitely encourage the use Nitrogen Boost during the veg cycle. I find that some gardeners that do not use Nitrogen Boost tend to use cal mag, but the reality of it is that the plants are reacting to the nitrogen and iron within the cal mag product. During this time is when plants are supposed to store up nitrogen and if they are not able to do this you will start to see what looks like a calcium or mag deficiency about week 3 of flower. Happy gardening!

Alan
Thanks for Rockin' House and Garden!
Alan W - Representative






On 2/21/2015 6:36 AM, I wrote:

Hi H&G,

Im using filtered water with a zero EC reading.
My question do I need to use a Cal Mag product in addition to your feeding schedule?
Im told that I do need to supplement but what do you think?


My set up:
RDWC 55 litre pots
Filtered water zero EC
Aqua flakes A&B
Multizyme
Amino
Root excel
PH up/down

Thanks,
Truman.
​

 

[blue]

Nice one true! Good reading!

It certainly confirms my thoughs on my N abundant calmag! I'd not heard of a PH stabalizer before so that's interesting too.

I was interested with their calmag addition holding pH stability for 2-3 days, becuase it also backs up my "lack of problem" theory from 30 days plus when i'm watering every second day. (Not giving the medium time to PH swing too dramatically)

It's all anecdotal for me .. but it's good!

I'm considering a PH stabalizer for earling watering now as i mull over the difference between PH change in the rez and PH change in the medium over time. .. The medium has buffers where the res doesnt, but i'm still considering that the PH may (still) be swinging too aggressively when there is too much gap between waterings (ramble ramble lol)

Cheers - Have a rep slap!



Blue ^_^

 

[pop22]

IMO your PH issues are related to the additives your using, not your RO water. I use General Hydroponics MaxiGrow and MaxiBloom for my DWC and my RO water remains stable for 7-10 days between res changes, with no more than a .1 rise. All good hydro nutes contain, or should contain PH buffers. Your plant would likely be better off without the extra additives, every DWC grow I've seen that has PH problems is adding 3-5 or more " additives" to their res, most of which do absolutely nothing but take your money! I've seen some killer grows using just Aqua Flames nutes. Think of it this way, if your nutes don't contain everything your plants need, why are they selling them?

 

[true]

Hey Blue, thanks for the slap

Hi Pop22 I dont have PH issues, I was writing to H&G for there advice. I wanted to know weather or not to use a Cal Mag product in my RDWC.
Ive never heard of this PH Osmosis Stabiliser, so wanted to get the AFN low down I hear ya on the additives, its so hard when starting out though. You want it all to be SO right and whats 10 or 20 dollars/pounds for a bottle of magic potion? Nothing at the time, then once you buy into one magic potion 2 magic potions is always going to be better right...

Anyone actually use this PH stabiliser stuff?

 

[Corgy]

Google pH osmosis stabilizer..... There is plenty discussions and "info" ...... And a very hung jury.....!

 

[eggmansky]

Hi All,

See below an email from me to House & Garden USA.
I'd be interested to hear your thoughts on this.


-------------------------------------------------------------------------------------

You will want to use PH Osmosis Stabilizer in this situation. There is PH instability that is associated with zero and low PPM water and this product will help to basically re-mineralize your RO water.

Cal Mag products are used by gardeners with RO water as a "band aid" type of fix to address this PH instability. PH Stabilizer will help to keep your PH more stable for up to 10 days where a cal mag product might only help stability for 2-3 days or less.

A cal mag product might be needed as an actual cal mag supplement, it really depends on the genetics you are working with. For the most part though, Aqua Flakes has a fair amount of cal/mag already in it and may not need more. Calcium toxicity is something to watch for if adding additional calcium. I definitely encourage the use Nitrogen Boost during the veg cycle. I find that some gardeners that do not use Nitrogen Boost tend to use cal mag, but the reality of it is that the plants are reacting to the nitrogen and iron within the cal mag product. During this time is when plants are supposed to store up nitrogen and if they are not able to do this you will start to see what looks like a calcium or mag deficiency about week 3 of flower. Happy gardening!

Alan
Thanks for Rockin' House and Garden!
Alan W - Representative






On 2/21/2015 6:36 AM, I wrote:

Hi H&G,

Im using filtered water with a zero EC reading.
My question do I need to use a Cal Mag product in addition to your feeding schedule?
Im told that I do need to supplement but what do you think?


My set up:
RDWC 55 litre pots
Filtered water zero EC
Aqua flakes A&B
Multizyme
Amino
Root excel
PH up/down

Thanks,
Truman.
​

Here's s'more...
http://www.myhydrolife.com/finding-balance-factors-affecting-ph-in-hydroponic-systems/

Finding Balance: Factors Affecting pH in Hydroponic Systems

September 20, 2012 | by Eric Hopper | Grow - Grow Master Class




Despite its important role in hydroponic gardening, pH has a nasty habit of being highly variable. But what causes this fluctuation and what can one do to stabilize it? Never fear, Eric Hopper is here to answer these questions.



Hydroponic growers understand the important role a stable pH plays in the performance of their garden. Sustaining proper pH levels ensures your plants maintain the maximum nutrient uptake level and large beneficial microbial population needed for a flourishing hydroponic garden. It doesn’t take long when monitoring the pH of a nutrient solution to realize that the pH is not a “set it and forget it” parameter. In fact, pH is continuously fluctuating. There are three major factors that contribute to pH fluctuation in a hydroponic system: the water itself, the nutrients used in the water and the medium or substrate used in the hydroponic system.

Water

Many growers do not know that water’s pH will fluctuate on its own depending on the surrounding environment. Reverse osmosis and freshly distilled water start with a relatively neutral pH (around 7.0), but the pH of this water will actually lower when this water is exposed to air. This is because the water absorbs carbon dioxide from the surrounding air. This fluctuation can be intensified in growrooms that supplement CO2, which is one of the reasons why so many indoor horticulturalists who supplement CO2 experience difficulty balancing their pH. In a CO2-enriched environment, it is not uncommon for neutral water to drop to a pH of 5.0 within a few hours. One way to minimize this effect is to remove the reservoir from the growing environment so it will not be exposed to high levels of CO2. Hydroponic systems where the nutrient solution makes minimal contact with the growing environment are less affected by the CO2-caused pH-lowering phenomenon.

Tap water is even worse in terms of pH instability because it is chock full of elements that will affect pH. Calcium and magnesium, which are known to cause pH instabilities, are probably the largest contributors to pH fluctuations in tap water. This is one of the reasons why so many hydroponic growers use filtration devices to remove excessive amounts of these elements found in tap water. Growers with hard water often experience constant problems with pH stabilization due to the high concentration of calcium and magnesium.

Nutrients

The nutrients used by hydroponic growers also have a direct influence on the solution’s pH. In fact, the higher the concentration (measured in parts per million), the greater the influence nutrients have over the pH of the solution. Nutrients affect pH in a few different ways. First, as the chemical compounds are broken down by enzymes or microorganisms, some are absorbed by the plant, but the remaining portion is left in the solution to contribute to the pH. For example, when a chemical compound is broken down for nutrient absorption and produces leftover molecules that are alkaline, the pH of the solution will rise (become more alkaline).

It’s not just the remaining molecules and their pH that affect the solution’s overall pH, however. The plants themselves, as they absorb nutrient ions, give off ions in return. For example, when a plant absorbs potassium ions, it gives off hydrogen ions in return. Hydrogen ions are acidic and result in a lowering of the pH. On the other hand, a plant gives off hydroxyl ions when it absorbs nitrogen ions, resulting in a rise of pH.

Growing medium

Last, but not least, is the medium. Although most growing mediums are stable, their chemical composition still affects the pH of the nutrient solution. There are countless chemical and biochemical processes happening in and around the medium, all of which affect the pH of the nutrient solution. Hydroponic gardening has an extremely high absorption rate and, teamed with a comparably high concentration of nutrients, the medium is ultra-sensitive to these chemical and biochemical processes. In nature, soil acts as a large-volume natural pH stabilizer. The pH stabilizer in hydroponic gardens is the solution itself, which is extremely weak in terms of being an effective buffer. As the concentration of a nutrient solution changes due to absorption by the plant or evaporation of the water, the pH will also change.

Hydroponic gardening speeds up virtually every biological process and, in turn, can accelerate pH fluctuations. In order to maintain a pH “sweet spot,” growers must gain a heightened understanding of all the contributing factors that affect the pH of the nutrient solution.

 

[Corgy]

http://chemwiki.ucdavis.edu/Physica...Temperature_Dependent_of_the_pH_of_pure_Water

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ChemWiki: The Dynamic Chemistry Hypertext > Physical Chemistry > Acids and Bases > Aqueous Solutions > The pH Scale > Temperature Dependent of the pH of pure Water
Temperature Dependent of the pH of pure Water
Table of Contents

1. A word of warning!
2. Contributors

The formation of hydrogen ions (hydroxonium ions) and hydroxide ions from water is an endothermic process. Using the simpler version of the equilibrium:


H2O(l)⇌H+(aq)+OH−(aq)


Hence, the forward reaction, as written, absorbs heat.

According to Le Châtelier's Principle, if you make a change to the conditions of a reaction in dynamic equilibrium, the position of equilibrium moves to counter the change you have made. Hence, if you increase the temperature of the water, the equilibrium will move to lower the temperature again. It will do that by absorbing the extra heat. That means that the forward reaction will be favored, and more hydrogen ions and hydroxide ions will be formed. The effect of that is to increase the value of Kw as temperature increases.

The table below shows the effect of temperature on Kw. For each value of Kw, a new pH has been calculated. It might be useful if you were to check these pH values yourself.

You can see that the pH of pure water decreases as the temperature increases. Interestingly, the pOH also decreases.

A word of warning!
If the pH falls as temperature increases, this does not mean that water becomes more acidic at higher temperatures. A solution is acidic if there is an excess of hydrogen ions over hydroxide ions (i.e., pH < pOH). In the case of pure water, there are always the same concentration of hydrogen ions and hydroxide ions and hence, the water is still neutral (pH = pOH) - even if its pH changes.

The problem is that we are all familiar with 7 being the pH of pure water, that anything else feels really strange. Remember that to calculate the neutral value of pH from Kw. If that changes, then the neutral value for pH changes as well.

• At 100°C, the pH of pure water is 6.14, which is "neutral" on the pH scale at this higher temperature. A solution with a pH of 7 at this temperature is slightly alkaline because its pH is a bit higher than the neutral value of 6.14.
• Similarly, you can argue that a solution with a pH of 7 at 0°C is slightly acidic, because its pH is a bit lower than the neutral value of 7.47 at this temperature.

Contributors

• Jim Clark (Chemguide.co.uk)

 

[Dr Who]

OK, I don't grow in hydro, but I have plenty of experience with the chemistry of aqueous solutions.

My take on the PH Osmosis Stabiliser is that it is probably just a simple salt, possibly with some buffering capacity. They are recommending it to "remineralise" RO water - the RO process is to remove minerals. They sell you the RO unit to remove the minerals, then they sell you new minerals to put in. Your water is pretty much back to square one, but your wallet is much lighter.

It's worth knowing, but rarely mentioned, that pH electrodes don't tend to respond well to very dilute solutions and will take a very long time to stabilise. I'm sure that this effect is probably contributing to the pH instability that they are trying to combat (it could be that the measurement is actually rather more unstable than the pH of the solution).