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Water pH alone has very little impact on coco grow pH

C

Carl Carlson

Wait, wait, wait.
I'm just reading the exerpt from the dosing handbook. It seems to be saying that from a practical point of view, lowering the PH of an alkaline solution is handled by adding acid.
Lowering the alkalinity however, is accomplished by adding acid.
Additionally, solutions with high alkalinity generally have high PH, ie are alkaline. Is that about right?

Yes, but to be clear, the solution doesn't contain alkalinity, it's the water that does with or without the nutrients.

Wouldn't it would be a lot easier if "alkaline" and "alkalinity" were not so similar and related at the same time?

I love how every publication about this topic starts out with a warning about that. Why did the scientists call it that in the first place? It's their fault.
 
C

Carl Carlson

i think thats the root idea of this thread... mostly straight tap water has excellent buffering capabilities and higher alkalinity than RO water. therefore being a PH nazi is not needed like it is with RO water... on the other hand without having an expensive water screening of your tap water, theres not telling what all chemicals and nutes are dissolved in your water... so why not raise the alkalinity of your RO water increasing its buffering capabilities? either way, i dont think RO is absolutely needed and many people out there prove that. the question is, will using RO water with added alkalinity be more effective than straight tap water? i think so as we are starting with a clean slate and injecting our nutes how we see fit. not starting with 300-700ppm water and adding nutes to that... who knows what the fuck is in there? unless we send our water into a lab for expensive screening...

That's a decent summary, but DO NOT assume that your tap water has low alkalinity. In the U.S. it largely depends on where you live. In have no idea about the tap water anywhere else. There are instances in which you would add alkalinity. Check out the article I posted by Matt Taylor on pH management or read the series from Bill Argo.

There are two main points to this thread. #1 - stressing the importance of testing your water for alkalinity and

#2 if you're growing in a soilless medium like a coco or a peat like many of us do on icmag.com, there is no combination of the things affecting water quality that will allow you to micromanage the pH of the medium the way some people think you can.

I'm not saying that you can't raise or lower the pH of the medium by a little bit or a lot over time, using the water and nitrogen as tools. What one cannot do is raise or lower the pH of the irrigation water to a certain number and expect the pH of the medium to instantly change to that number.

You'll note that I still pH target the water in my bubble cloner. And if you're growing in coco and foliar feed than by all means, pH target the water. This is all about the relationship between the water and the medium, because I'm not using water as the medium.
 

p0opstlnksal0t

Active member
That's a decent summary, but DO NOT assume that your tap water has low alkalinity.

i think the opposite is true in most cases, where the tap water has high alkalinity... but you are right, i would not base anything on assumption! get a test kit, which can be found at aquarium store that test ph, gh, kh, etc... then you will know what your workin with...:dance013:gl


heres a good kit for cheap (please visit at your own risk) : http://www.opentip.com/Pet-Supplies/Freshwater-Master-Test-Kit-p-751719.html

"Tests include: freshwater pH, high range pH, ammonia, nitrite, GH (general hardness) and KH (carbonate hardness). Kit features 4 test tubes, a holding tray for testing bottles and test tube rack."
 
C

Carl Carlson

by the way nice screenname

You are correct, I misread this sentence.

mostly straight tap water has excellent buffering capabilities and higher alkalinity than RO water.
 

p0opstlnksal0t

Active member
by the way nice screenname

You are correct, I misread this sentence.

haha ya thanks bro, that pond test strip should get you on point in regards to where your tap water sits at... id check it at least every 2 mos. it can change some and might lose or gain ph or kh from rainstorms and droughts n shit like that.
 
B

bonecarver_OG

anyway just wanted to add the thread is cool :D and i like how its going :D

I'm guessing there many growers using RO or distilled water that don't realize they contain zero alkalinity

that is defiently true. bullseye!

i think the great majority of growers dont have enough understanding on a whole about this complicated matter, and maybe a lot of ppl are fooled to use RO water without really having to.

for years i have strongly adviced coco growers to use tapwater mixed with RO or distilled water. i have been using rainwater to lower the ec of the tap water for the past half year with great results.

i have never seen any need of adding MG under normal circumstances, so i think in the great whole the idea is good to use tapwater.

even though tap water can contain in some areas, aditives that are not good for growing, it will in most cases have a better range of trace minerals compared to only RO and distilled water. if the content of minerals is too strong its an easy thing to adjsut with RO water and similar....

bicarbonate and other mineral salts is the problem, not calcium and mg content of the tap water, atleast not in general.

here in spain in some areas the water is far beyong hard, and reaching almost an EC of saltwater i.e SEA water. thats how hard it is in some places. there is a lot of mineral foundings in most of spain, and the karstik geology make for a lot of minerals contained within to leech into the ground water. amongst these are gypsym and similar easilly disolvable minerals.

it all depends a lot where u live, tap water trace mineral content varies a lot, depending on surrounding geology etc

best bet is as stated allready in this thread by other, test your water :D

lots of good info in here :D

peace!
 

p0opstlnksal0t

Active member
here in spain in some areas the water is far beyong hard, and reaching almost an EC of saltwater i.e SEA water. thats how hard it is in some places. there is a lot of mineral foundings in most of spain, and the karstik geology make for a lot of minerals contained within to leech into the ground water. amongst these are gypsym and similar easilly disolvable minerals.

how does it taste right out of the tap bro? bet that shit has some kick!
 
B

bonecarver_OG

in general the tap water is not for drinking...

even using it for boiling will ruin pots etc. bottled water is the way to go.

i even feel bad to give the tap water to my cats, thats how i feel it. the EC here in my region is hard but not amongst the hardest in spain. my tap water is 1.0 EC - and half hour by car away where my coop-partner has his setup, the tap water is much higher, i think i remembered it to be around 1.4 EC. having rainwater collection systems is a great help for any gardener here. also it is possible to get well watered of high quality delivered by truck, about 5 m2 in one go so many older houses (depending area) have these drinking water wells that get filled up by delivery, but today its used to showers and such most of the time.

anyway, there is many plants that dont mind higer EC in the water for irigation, so this area is inspite of how it mind sound, the most agriculturally rich area of europe. most veggies in europe is from here. not to talk about spanish oranges...

so in toher words :D

nothing is impossible.

also there is experiments in spain using alternative acids for PH down, because some acids dont react as strongly/quickly with the alkaline compounds depending on mineral content of the irigation water..

peace
 
F

feral

Interesting thread. esp. appreciate the FAQ from Farfard that you added since that's what I've been using the past few grows. Answered a question I had concerning my plant growth at times. Thanks
 
In other words if you are using R.O. or distilled or tap water with low alkalinity like I have than the pH of your irrigation water quickly changes to the pH of the soilless medium because the water has little to no buffering capacity. That is what alkalinity is.

it seems as if your confusing your alkalinity with your TDS or your solutions amount of buffering capacity. Alkaline....or basic... are terms for a solution being above 7. Alkalinity...or "low alkalinity" would probably mean, while its not that strong of a basic solution...it still has more alkaline character than acid. i hope that makes since....

but you did mention a valuable point about buffering capacity. the relatively clean or purified or even some pure tap water has a low amount of total dissolved solids...in general. these specific types of ions make for the solutions to be either acidic...basic...or even neutral pH 7. so water has a low amount of these, as compared to when you dump a tbsp of of nutes in there. These small amounts of ions found in the tap water have a poor buffering capacity, compared to the larger amount of nutrients, or total dis. solids you just added.
edit- also, the buffering capacity is noted with a pH change once youve added enough TDS or ions to 'break' the capacity of the solution to hold its current pH. thats basically the definition of a buffer. does this make any since? maybe this ecsd got me rippped
 

Slimm

Member
Alkalinity is a measure of the ability of a solution to neutralize acids to the equivalence point of carbonate or bicarbonate. Alkalinity is sometimes incorrectly used interchangeably with basicity. For example, the pH of a solution can be lowered by the addition of CO2. This will reduce the basicity; however, the alkalinity will remain unchanged.

So has anyone determined the optimal range for alkalinity in RO, and what are the best ways to increase alkalinity of RO water?
 

osirica420

Active member
Just thought i should share this...
I have grown 100% organically in a DWC without modifying the PH..
even when it rose to 7.5 at times for days and was all good...

near the end of flower it kept going acidic and i had to keep changing the water it was prolly root rot though that caused that problem(too much guano and molasses)..

If it wasntt for that it would of been a problem free healthy grow!
here is are some bud shots..


picture.php

picture.php
 

BENJI

Between the Devil and the deep blue sea...
ICMag Donor
Veteran
This is a very interesting thread love all the info keep it coming people..!!!
 
Last edited:
C

Carl Carlson

So has anyone determined the optimal range for alkalinity in RO, and what are the best ways to increase alkalinity of RO water?

The R.O. process removes alkalinity.

Match your water quality with the correct nutes.

Use nitrogen content to control pH vis a vis alkalinity in container grows.

edit: I don't know if it was mentioned on this thread already, but the only liquid hydro nutrient that I've found on the market so far that contains a relatively high % of ammoniacal N is Dyna-Gro Grow and Bloom with IIRC 20% ammoniacal N. GH 3 part and FNB / FNG are around 6% ammoniacal N.

FYI

Addressing pH Problems
Fine-tuning your substrate pH is all about the nitrogen. If you control it, you’re in control.


By Matt Taylor and Dieter Lohr
January 2010


Bill Argo is also all over this topic. I posted his links on the previous page.
 
C

Carl Carlson

it seems as if your confusing your alkalinity with your TDS or your solutions amount of buffering capacity. Alkaline....or basic... are terms for a solution being above 7. Alkalinity...or "low alkalinity" would probably mean, while its not that strong of a basic solution...it still has more alkaline character than acid. i hope that makes since..

No, you need to go back to the beginning.

Ignore the fact that this was written for people in the state of Kentucky because I like the way this link is written.

Alkalinity and Water Quality

Alkalinity (Buffering Capacity)

Alkalinity refers to the capability of water to neutralize acid. This is really an expression of buffering capacity. A buffer is a solution to which an acid can be added without changing the concentration of available H+ ions (without changing the pH) appreciably. It essentially absorbs the excess H+ ions and protects the water body from fluctuations in pH. In most natural water bodies in Kentucky the buffering system is carbonate-bicarbonate (CO2HCO3 CO32-). The presence of calcium carbonate or other compounds such as magnesium carbonate contribute carbonate ions to the buffering system. Alkalinity is often related to hardness because the main source of alkalinity is usually from carbonate rocks (limestone) which are mostly CaCO3. If CaCO3 actually accounts for most of the alkalinity, hardness in CaCO3 is equal to alkalinity. Since hard water contains metal carbonates (mostly CaCO3) it is high in alkalinity. Conversely, unless carbonate is associated with sodium or potassium which don't contribute to hardness, soft water usually has low alkalinity and little buffering capacity. So, generally, soft water is much more susceptible to fluctuations in pH from acid rains or acid contamination.

Methodology: Alkalinity is an electrometric measurement which is performed by the computer aided titrimeter (CAT) and the pH electrode. A potentiometric titration is taken to an end-point reading of pH 4.5. The amount of acid required to reach a pH of 4.5 is expressed in milliliters. The calcium ions (CO3) neutralize the acid in this reaction, and show the buffering capacity of the sample. From the amount of acid used, a calculation will indicate the amount of carbonate (CO3) involved in the reaction. This then is expressed as mg of CaCO3/L even though actually part of the alkalinity may be contributed by MgCO3 , Na2CO3 or K2CO3.
 
C

Carl Carlson

here in spain in some areas the water is far beyong hard, and reaching almost an EC of saltwater i.e SEA water. thats how hard it is in some places. there is a lot of mineral foundings in most of spain, and the karstik geology make for a lot of minerals contained within to leech into the ground water. amongst these are gypsym and similar easilly disolvable minerals.

it all depends a lot where u live, tap water trace mineral content varies a lot, depending on surrounding geology etc

Hi bonecarver, sorry if I was defensive in the first reply. You people in Europe are dealing with a whole other situation when it comes to tap water. Like you said, it's seawater. It's desalinized but still has a high EC, is that right?

In the U.S. - we get much of our water from freshwater streams, rivers, wells, etc.
 
C

Carl Carlson

seedlings moving along nicely, now "under" the 2nd 600w HPS. the xpansion has begun. here is one half of them:


day 15 of bloom


fan leaves on the main stem, accept for the top two and some lower branches well below the light have been removed.
 
B

bonecarver_OG

Hi bonecarver, sorry if I was defensive in the first reply. You people in Europe are dealing with a whole other situation when it comes to tap water. Like you said, it's seawater. It's desalinized but still has a high EC, is that right?

In the U.S. - we get much of our water from freshwater streams, rivers, wells, etc.

it all depends a lot on the area where ppl live :D as as stated before even rivers mineral content is affect by the minerals that it drags with it on its way.

the desalinized water is actually not as desalizined as one would hope for, and this i think must be mainly because of the enormous cost of evaporating water to de mineralize it, specially since i dont think almost any instalation here is neither modern nor eficient. anyway :D lot of the salt remain in the water :D this is mainly a problem for mediteranean costal regions. inwards land the deal is most of the time better.

also there is lots of places where even the ground water is salty, as for example other area where there is high salt content in the earth crust. where there is salt-mines, ur best bet is not to use too much tap water.... but on the other hand, there is ppl that are blessed with pristine tap water.

but in europe in general the tap water is really clean and good to use, althought in some areas it might be rich in Calcium.

im sure without no doubt areas like coastal spain, (mediteranean france maybe), coastal areas of italy, greece and former yugoslavia might have problems, depending on local water supply qaulity.

anyway :D its a matter of analysing a water sample to really know how it is..

i hope this thread might give ppl that live in areas with good water more confidence to NOT to use all RO water..

peace :D

:D
 

osirica420

Active member
small amounts of salt is beneficial my brothers, least for plants...

checkout my sig , i been growing with sea salt minerals for over 2.5yrs now...
 

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