RO Water & Water Quality.

azee_2009April 1, 2010

Hello Everyone,

I am new to hydro..!

The problem I am facing is:

PH that is adjusted at 6.3 or 6.4 swings up in between 7.3 to 7.6 after 24 hours intervals. This is due to the buffering capacity of the water. Which is a great problem to re-adjust it again & again?

I have been sujested give a try to my mini RO system that was attached to our kitchen sink couple of years ago & was removed after words. I have to add just two new cartridges to it.

It is 3 stages RO system. Two stages hold cartridges where as third one is UV sterilizer.

If this will OK to triumph over PH undue swing?

What specific cartridges I need to install in 1st two channelsÂ? What is their specific name or identification?

Should I switch ON UV sterilizer while processing water?

If this kind of drawn water will be ready to use as hydro.

Regardless of efforts or cost, what do you all guru-s prefer me to do, whether to for boil water, Ro water or distilled water? Which will be the best in my case?

I have to proceed for small setup & this will be my 1st successful attempt ever.

Plz also reply the following as I also tried this...!

@ PH of boiled water is 8.4 after 13 hours of boiling. Is it normal?

@ PH of water by homemade distelation is 8.0. Is it normal?

Awaiting help from GURUs


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''Regardless of efforts or cost, what do you all guru-s prefer me to do, whether to for boil water, Ro water or distilled water? Which will be the best in my case?''

Definitely use the RO water!!! Will be a great decision. Wish I had the money to go get one of those myself ; ) The water will be, dare I say, 100% clean!! Which answers another question...

''If this will OK to triumph over PH undue swing?''

Yes, this will more than likely trump any of the salts, chlorine and other particulates which are notorious for raising pH. Now, when you said: ''PH that is adjusted at 6.3 or 6.4 swings up in between 7.3 to 7.6 after 24 hours intervals'' are you saying that the water raises in pH after just sitting out for 24 hours, or do you mean that the pH rises after being placed in your hydro system whilst it is on and running with nutrients??

I ask because some nutrients have the ability to raise your pH a decent amount. Other brands claim that their nutes contain buffers (some, like mine, actually do) which help the pH to be maintained at a constant level of 6.0-6.5.
Of course you may need to adjust your pH from time to time but nothing huge to worry about. Though this in fact will not matter when you get your RO up and running!

As for the type of filters your needing to buy I will be honest and tell you that I have no idea! May I ask what brand or type of RO system you have?? That may help others to answer your question.

Hope I helped you at least a little bit

    Bookmark   April 1, 2010 at 11:51AM
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Azee, just a thought, but how did you boil water for 13 hours, without it all evaporating? :~)

For a typical RO unit, there are three filters. Two sediment filters and a membrane filter, that takes all the chemicals like chlorine out. I'm not sure about the UV filter, that might be a new model. I know they use UV in pond pumps to clarify the water. Anyway, the RO filter works great, but you will have to supplement with cal/mag.

One more thought, depending on your reservoir size, it might be more cost efficient to buy 2.5 gallon distilled water from the grocery store. It's filtered using reverse osmosis(RO) and the cost is $2.50 or so. You could always catch rain water, if you live in a house with gutters?

    Bookmark   April 1, 2010 at 11:09PM
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What happens is that the basic/alkaline components (mainly calcium) that are responsible for the high PH (as in 7.3 or 7.6) also buffer it together with the more neutral components. As soon as you add SOME acid, the basic elements neutralize it in 24 hours, but loose some potency, respectively get eliminated partially within the "reaction". If you repeat that process, the alkaline components- and their buffer capacity get lower and lower until the alkaline buffer is "gone". The "last" time you add ph-down/acid to your water, it will drop drastically to perhaps under 5. This mostly happens when a week PH down is used repeatedly. With Nitric acid at 75 or 95 %, this will not happen, it will get the alkaline elements down in one shot. But that is the stuff that burns through concrete floors like alien blood and it's truly not everyone's cup of tea. If ever you can lay hand on it in the US without an explosive license. ;-)

PH of boiled water of 8.4 after 13 hours of boiling is "normal" because you evaporate lots of water, while calcium and other alkaline elements (already responsible for the high pH) remain in the water and hence will be present in higher concentration and push up the pH. There may also be some chemical reaction and transformation within these 13 hours of boiling, I don't know of.

Nutrients generally lower and buffer a certain pH, that's what any mineral composition with an acidic sum, added and dissolved in water does anyway. NUTRIENTS are actually made to lower the PH, as the usual 7+ is not suited. The only difference is that some manufacturers point this out explicitly while others don't. Some manufacturers may indeed add some more of specific components like mono potassium phosphate that helps lowering and buffering such Ph, but that's pretty much it. As a side effect (when running higher EC) you may have excessive Phosphorus that will result in Ca deficiency.

But in this context it is important to know that a higher nutrient concentration will lower the pH more than a weaker ratio. Hence in some cases it's not a bad idea to simply (slightly) increase the nutrient concentration by a click or two. It's also a reason why some manufacturers recommend higher concentrations as needed, and some commercial growers push the nutrient concentration higher.

If the PH of the base water is too high, most nutrients can't bring it down to around 6 and that's (only) where pH down- as in acids or other components are required. In ANY case it is always best to have, use or get water that is around and not (much) over 7.

RO water is fine, but take care what nutrients you use, as with some extra acidic nutrients (many are developed with areas in mind that have an excessive amount of calcium carbonate in the (well)water) you may end up with an unwanted but extraordinary low PH as well.

Attention, Ph and EC are interconnected, EC reading of a nutrient solution will not be the same at PH 5.0 as it is at 7.0!

    Bookmark   April 2, 2010 at 3:25AM
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Hello Everyone,
1st of all thanks a lot to ethnobotany, urbangardenfarmer & lucas_formulas.

@ ethnobotanyÂ!
PH rises after the nutrients being used to feed the seedlingsÂ!
I have made homemade MOD Hoagland Nutrients to run the system. Diluted Sulfuric Acid is used to lower the PH. I do hope my RO will do the best.
Mine RO water filter is same like as link below:

@ urbangardenfarmerÂ!
I must apologize to cause the trouble to you for the following:
Water was boiled for half an hour & let it sit for 13 hours, then I scoop off the scum from the top and pour off the clear water for use leaving the calcium carbonate chips behind in the pot & after pouring its PH was 8.4.
I shall arrange two sediment filters & one membrane filter.
I am thinking about to remove UV module function. Plz see picture as linked above & direct me that at which end the membrane filter should be or at which end both of the sediment filters beÂ?

@ lucas_formulasÂ!
Thanks for the discussion.
Relatively high nutrients concentrations method seems to be good idea to give a try. I shall try it on direct raw tap water. I am currently adding below concentration of nutes to 5 US gal bucket.
Calcium Nitrate: 133 ml what should it be to give a try?
Potassium nitrate: 95 ml ?
Potassium Dihydrogen Phosphate: 38 ml ?
Magnesium Sulphate: 38 ml ?
Micro Nutes: 19 ml ?
Chelated Iron: 19 ml. ?

I use diluted Sulfuric Acid for ph down.
Awaiting for further discussion.

Here is a link that might be useful:

    Bookmark   April 3, 2010 at 7:23AM
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Awaiting for further proccedings on my reply posted above.

    Bookmark   April 4, 2010 at 3:09AM
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Salam and patience Brother Aziz,

I haven't got the time to look into your formula yet. I originally use gram per Liter for components and ppm for elements. Hence, ml to 5 US gal doesn't ring a bell with me at the first glance.

Is that recipe based on the so called modified Hoagland formula? Sometimes it's even given in Millimolar... and not sure if it's always the same, as Dr. Hoagland and friends actually used quite a bunch of formulas.
Don't you have it (this one) in gram/liter - If so, I could type it in my spread sheet and tell you what it looks like and for what use it might be suited.

Also, if I remember well the Hoagland formulas were originally used in quite high concentrations at the time - and in case, I wouldn't recommend to actually increase the EC.

    Bookmark   April 4, 2010 at 4:02AM
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Salam too.
Thanks for the post.
Yes it is based on Modified Hoagland Solution & it is also given in Millimolar. I will check it tonight & inform you how much grams of each specific diluted chemical is used to mix with each liter of water in reservoir. I use to consider that there are 19 litres of water in a five gallon bucket though actually 5 gallon bucket holds 18.9 litres of water.
Best regards.

    Bookmark   April 4, 2010 at 4:26AM
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Please azee, consider that what you gave here is ml (milliliter) per component, which is normally a solution of a mix of water and the respective component. And even if I can transfer gallons to Liter (quite easily) I can't guess the gram contained in 1 Mililiter of said solution. You may not have realized it, but unless the gram per ml aren't known as well, the formula isn't conclusive. ;-)

    Bookmark   April 4, 2010 at 5:16AM
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Hi Again,
Now please check it:
These are my 6 stocks:
Stock No 1: Calcium Nitrate, 1000 grams were mixed with 4 liters of water. Molar mass is (236.1 g/mol)
Stock No 2: Potassium Nitrate, 404.4 gram were mixed with 4 liters of water. (101.1 g/mol)
Stock No 3: Potassium Dihydrogen Phosphate, 544.4 grams were mixed with 4 liters of water. (136.1 g/mol)
Stock No 4: Magnesium Sulphate, 1000 grams were mixed with 4 liters of water. (246.5 g/mol)
Stock No 5: Below all five chemicals were added to 4 liters of water:

H3BO3 12 grams
MnCl2.4H2O 7.2 grams
ZnSO4.7H2O 1.2 grams
CuSO4.5H2O 0.4 grams
NaMoO4 0.4 grams

Stock No 6: Chelated Iron 216 grams (not by volume) of (3% Iron) was added to 4 Liters of water.

Is it that you want me to doÂ?
Awaiting reply.

    Bookmark   April 4, 2010 at 6:17AM
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I've got it, but I had to draw it down to some "reasonable" data - as the method and the way of proceeding is a bit outdated. Well yes, the original formula dates from 1930 something ;-)
When formulating for 1300 Liter with the basic components and their actual proportion in the solution, the formula (like nutrient makers mostly use to think of a formula), would look like follows:


It's actually a good thing to use 5 components, but using distinct quantities of each on top of it, isn't exactly pragmatical for average users. That''s why modern nutrients get basically split into only 2 components. If transforming the formula for a modern recipe, it would look like follows:

IMPORTANT remark: I didn't convert the actual trace elements (too time consuming) but did use another reference ->

*Cu =0,26
Mo =0,05

* as I can see here, the Cu part is a bit off target, with 0.06 you'd need 0.24g only!

With this recipe for 1300 Liter (at a concentration of about 1.72 mS/cm) you only need to use equal parts of A and B. Use at least 5 Liter (total with all components included) of water for each component and dilute accordingly for the use as a nutrient solution. If using 6.5 Liter (x2 as in A and B) you've got an easy to calculate 1:100 concentrate.

PS: all data are approximations and depend on actual purity of each used component. These calculations are based on a purity of 100%, which isn't actual in most cases. 97-98% would be more close to actual purity.

    Bookmark   April 4, 2010 at 8:10AM
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Thanks a lotÂ!
Though the calculations are bit technical, I have followed to some extant.
Summarizing, would you please suggest the quantities to give a try for PH swings problem as under:
Calcium Nitrate: 133 ml what should it be to give a try?
Potassium nitrate: 95 ml ?
Potassium Dihydrogen Phosphate: 38 ml ?
Magnesium Sulphate: 38 ml ?
Micro Nutes: 19 ml ?
Chelated Iron: 19 ml ?

Please take into consideration that by reservoir is 19 liters.
Awaiting anxiously.

    Bookmark   April 4, 2010 at 10:09AM
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It's late here Brother, will get back to you tomorrow.
What I can tell you for now and straight away, is that you can't change much here, to alter PH, by simply modifying some proportions.


    Bookmark   April 4, 2010 at 11:20AM
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Ask kiya haal hain, Azee Bhai?

Sorry, I am a bit busy lately and I'll keep this brief:

The formula looks like being a typical lettuce or "green" formula for cooler climate. It's quite generous in Ca and high in N. I believe this is part of the high PH, respectively why the nutrient isn't getting PH down further.
But looks like the concentration is high (enough), I wouldn't increase it for standard use (lettuce).

Not sure about the region you are at, more like around Karachi (south) or more in the north - but I believe you have spring or summer now. Anyway, an alternative formula for warmer climate would have more potassium content and less nitrogen. Best is to cut on the Calcium Nitrate by using only 100ml, Magnesium sulphate use somewhat more, 42 ml, potassium nitrate use 115 ml. Potassium Dihydrogen Phosphate 43 ml. Later mod is a bit against my own principles (of lower phosphorus) but still Ok, as in the original formula it is quite low and increasing it isn't a fancy thing to do. It is an acidic component and might stabilize PH somewhat. Everything else: use same as before. After making up the nutrient solution check the PH (1. afterwards and 2. after letting it sit for a while, and again the next day) and tell me if there is any change or improvement. This new formula should bring the PH down at least a bit.

PS 1: don't use any of your "cooked" water.
PS 2: get that RO unit working and you'll have one more option to improve PH. You may even use 50/50 tap and RO water to take profit of some extra minerals from the tap water and low amounts of chloride and Na.


    Bookmark   April 5, 2010 at 10:10AM
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Aslamu Alikum! Lucas Bhai, Apna sahi naam to batayain janab..!
How are you? Believe that you will be absolutely fine.
I am Azee & residing in Gujranwala, Pakistan.
Plz also visit my site as for my complete introduction.
Please introduce your self completely. WhatÂs you name? Are you Muslim too & an agriculturist residing in Thailand? Please give me your email Id, phone number, cell number & address & so on. I shell call you to have more conversation.
I will go through according to your guide lines & shall inform you the results.
Since we were in negotiation, I experimented the following:
 On March 30, I used raw tap water to fill 5 gallon bucket & added nutes as described before. Adjusted the Ph at 6.0 that raised 7.2 after 24 hours interval.
 On March 30, I also had reserved BOILED water in other bucket & on the boiling date its PH was 8.4. For onward three or four days I lowered the PH again & again by diluted sulfuric acid. I observed that its buffering capacity is being reduced by the time. I reserved it to use it to top up water level of my 5 gallon bucket. I used ½ liter water daily to top up my 5 gallon bucket.
 Ph level of my 5 gallon bucket to feed cucumber & bitter gourd seedlings is going very stable now.
 On April 2, Ph was adjusted at 6.0 that raised 6.6 after 24 hours.
 On April 3, Ph was adjusted at 6.1 that raised 6.5 after 24 hours.
 On April 4, Ph was adjusted at 6.2 that raised 6.4 after 24 hours. (No ph down was used but water added)
 On April 5, Ph was adjusted at 6.4 that raised 6.6 after 24 hours.

There seems to be very much stable ph & no more fluctuation now. ItÂs very hot summer going now.
Plz comment over the situation

I will proceed with your newly recommended concentrations very soon.
My proposed feeding timetable will be as under:
On day one, April 2, (FRIDAY) the raw tap water & nutes were added to the 5 gallon reservoir. That water will last for 21 days & will daily be refilled with reserved boiled water to the point marked. This all will last for day one to six.
On day seven, APRIL 9 (FRIDAY) one more nutes lot will be added to same water & the water be refilled with tap water to the point marked. This all will last for days eight to thirteen.
On day fourteen, APRIL 16 (FRIDAY) one more lot of nutes will be added same water will be topped up. This all will last for days fifteen to twenty.
Same will be the plan for next 21 days. (Means it will start all over again with all newly picked water & new nutes on April 23 (FRIDAY).
Awaiting comments.
Thanks a lot in advance.
Best regards

    Bookmark   April 6, 2010 at 6:47AM
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Dear Brother,
Have you checked the link above to see link to my RO system..? It it OK?
Thanks a lot & take care

    Bookmark   April 6, 2010 at 6:58AM
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Alalaikum-u-Asam, Azee Bhai

Where shall I start? ;-)
Briefly about my religion and views, (it would be impolite to leave it out, but I wont go into details either, because it is subject to some discretion). Well, technically I am not a muslim but I am quite familiar with islamic traditions because of relatives and friends. I used to study Sufism when I was younger and actually still am member of such a Brotherhood. Btw: here in Thailand Buddhist call each other Brother or Sister as well, so it is not unfamiliar at all ;-) Besides I am a fan of Qawwali music and Nusrat Fateh Ali Khan!

It's very hot here too, I believe we reached 39° C today. I am flanked with two fans from each side! LOL

Back to topic:
Your high and alkaline buffered PH is mostly (only) due to water hardness in combination with high calcium content of that H.M. formula. What happens is that you burn out the calcium little by little out of the water. In fact it''s the other way round, the high calcium neutralizes the Phosphorus acid, each time you add it, until it gets dissolved by the reaction. It's much better to have less calcium in the first place by a lower calcium content in both water and nutrient composition.

In fact you increase the phosphorus content in your water and make the remaining calcium unavailable at the end. Get the RO unit in shape (replace the filters), - you can use the UV unit but it will not be of much use at that state. As a result you will have much softer water and with a lower calcium content (and more acidic components), your starting PH will be much closer to 6. As for now, I wouldn't target the optimum (around 6.0) but settle for 6.5 until you change your strategy as I described.

As for a personal contact, I'd love to get in touch with you after having a look at the website. An you are located in Punjab and into seeds, wow....I will contact you via your website soon!

Take care!

    Bookmark   April 6, 2010 at 9:05AM
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Too silly we can't edit any posts with this forum software and if you are in a hurry between things... :-(
I need to apologize and correct:

The greating should of course be spelled "Alaikum alsalam"

sorry for the miss spelling Brother Azee!

    Bookmark   April 6, 2010 at 9:20AM
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Have send the email at your Email ID.

    Bookmark   April 7, 2010 at 8:06AM
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