# RO Water PH 8.5????



## bushmang (Aug 25, 2009)

hello everyone i am having some ph issues I have a RO pump and i pumped some water into my RO tank about a week ago i have been having some ph problems in my nutrient tank as well.

Now my RO water is at 8.6 is this normal?

the water in my nutrient tank is very difficult to control i drop the ph down to 5.8 and the next day its back up to 7 i have been doing this everyday for about a week now and almost a full ph down later its still doing it.

Any ideas? is my ro pump fucked up? am i doing something wrong? any help is apreciated im confused at this point


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## bushmang (Aug 25, 2009)

the water out of my osmosis pump is at 8.0. that would explain the spike in the RO tank due to evaporation. Isnt RO water supposed to be at 7.0?


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## RickWhite (Aug 25, 2009)

Yes, RO water should be 7. Your RO unit is defective and you most likely have hard water. I bet the ec is way up there too.


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## tSunami13 (Aug 25, 2009)

bushmang said:


> the water out of my osmosis pump is at 8.0. that would explain the spike in the RO tank due to evaporation. Isnt RO water supposed to be at 7.0?


No RO water does not always have to be 7.0. Check this out it is about dissolved gasses in RO water and how it affects the final RO pH. http://www.freedrinkingwater.com/water-education2/ro-ph.htm 
I have been to many fish stores to get RO water and none of them have ever been the same pH.


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## tSunami13 (Aug 25, 2009)

If you are getting low ppm's out of your RO it is working properly. Most RO units do not adjust the pH. There are extra stages of filters you can add to do that though.


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## bushmang (Aug 25, 2009)

nice guys thanks for the info. my ppm is looooow so its working. the ph coming out of the pump is 7.9 i just checked so it should be good right?


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## tSunami13 (Aug 25, 2009)

bushmang said:


> nice guys thanks for the info. my ppm is looooow so its working. the ph coming out of the pump is 7.9 i just checked so it should be good right?


Yeah your water should be good. Just add the nutes and then slowly adjust for pH if needed. Most nutes will drop the pH into a good range. Just be sure to make small adjustments if adding pH down as it takes a few hours for it all to settle down and become steady.


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## Roseman (Aug 25, 2009)

https://www.rollitup.org/hydroponics-aeroponics/230241-water-question-ro-distilled-ph.html

good info on water there


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## desert fox (Aug 25, 2009)

Well your getting low ppm so your checking the right line. My first guess was that you were checking the waste line. 

Is your PH meter accurate? 

How old is the unit? Backflushing is pretty easy to do just by changing some hoses around. 

8.6 seems way off to me. Generally as the membrane gets worse it will drop your PH. Low 6ish is the worst I have seen in a commercial application. Has your membrane ever dried out? Has your RO unit been sitting idle for a long period of time? These can cause a higher PH.


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## bushmang (Aug 27, 2009)

Ph meter is on point, the unit is about 3 weeks old. i just checked the ph on my tap water and its at 9. the unit is working due to the low ppm my tap water is coming at a really high ph. the ro ph is at 8 so im sure the unit is workig. it sat for maybee two weeks not in do u think the membrane coul dhave dried out?

how do you back flush



desert fox said:


> Well your getting low ppm so your checking the right line. My first guess was that you were checking the waste line.
> 
> Is your PH meter accurate?
> 
> ...


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## desert fox (Aug 29, 2009)

just cuz your meter is new doesn't always make it on point. I had to return a milwakee meter cuz it would stay calibrated. It was consistantly giving me a ph lower by around .5 to .8 lower than actual. 

I haven't ever heared of tapwater as high as 9.0. I really think your meter might be the problem. 

backflushing is just passing UNCLORINATED WATER over the membrane to lossens any minerals that may be clogging it. They make backflush kits for it. or you can just do a very primative by just swithing hoses. Just make sure that your water goes threw your sediment and carbon filter first and you cant fuck it up. Carbon will remove clorine. It just helps to get your rejection rates lower.

Your TDS is fine. I would almost bet money on it that your RO water has an actual PH of 6.8-7.2 

2 weeks sitting idle if fine. I was talking about like 2 months or more.


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## Deezy85 (Feb 22, 2020)

It all depends on what the untreated water pH is, the RO itself does no change pH much, if your ppm’s are low then search any pre or post filtration units as the likely cause. Using activated carbon in pre-treatment?


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## cannabineer (Feb 22, 2020)

bushmang said:


> hello everyone i am having some ph issues I have a RO pump and i pumped some water into my RO tank about a week ago i have been having some ph problems in my nutrient tank as well.
> 
> Now my RO water is at 8.6 is this normal?
> 
> ...


Tiny [H+] differences can drive large apparent pH differences. Add one (1) drop of sulfuric acid and note the new pH. IMO (I’m a chemist) nonissue.


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## Nizza (Feb 22, 2020)

I don't use my pH meter in my RO water until I add nutes cause I thought straight RO fucked up the wick or something. I thought pH was irrelevant in RO water until u add nutes


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## fragileassassin (Feb 22, 2020)

Deezy85 said:


> It all depends on what the untreated water pH is, the RO itself does no change pH much, if your ppm’s are low then search any pre or post filtration units as the likely cause. Using activated carbon in pre-treatment?


You should probably try a post that hasnt been 11 years since the last comment


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## cannabineer (Feb 22, 2020)

Nizza said:


> I don't use my pH meter in my RO water until I add nutes cause I thought straight RO fucked up the wick or something. I thought pH was irrelevant in RO water until u add nutes


RO water has super low PPM which gives the pH electrodes a comprehensive conniption. All smooths out when you add some ions.


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## Deezy85 (Mar 14, 2020)

fragileassassin said:


> You should probably try a post that hasnt been 11 years since the last comment


Thanks. Always feels good to have thread police on the scene, keeping everything in check, all without anyone asking you to. Don’t be that guy douche. Old threads stay on here for a reason, the information doesn’t stop being useful. Why you find it important to be a smart ass for someone commenting on an old thread is beyond me but I think it’s what makes you head of the volunteer thread police, it’s in your DNA, it’s your calling and kudos to you for finding your passion. DidnI mention you are a douche?


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## Renfro (Mar 14, 2020)

A little late but for others that may have a similar issue, make sure the RO filter doesn't have an alkaline post filter that adds minerals back to the filtered water and thus raising the pH.


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## fragileassassin (Mar 14, 2020)

Deezy85 said:


> Thanks. Always feels good to have thread police on the scene, keeping everything in check, all without anyone asking you to. Don’t be that guy douche. Old threads stay on here for a reason, the information doesn’t stop being useful. Why you find it important to be a smart ass for someone commenting on an old thread is beyond me but I think it’s what makes you head of the volunteer thread police, it’s in your DNA, it’s your calling and kudos to you for finding your passion. DidnI mention you are a douche?


It was a literal comment you fucking cuck. 
You arent going to bring people back from the dead. youve seen how active this post has been since youdug it up from the grave. Most ppl see the date and skip it.


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## PissingNutes (Mar 29, 2020)

Meters should be re-calibrated often.
Like tSunami13 said dissolved gas will show high PH.


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## Renfro (Mar 29, 2020)

PissingNutes said:


> Like tSunami13 said dissolved gas will show high PH.


That is the truth, I have an Apera pH meter and when I try to take a reading off a tank with air stones going the reading is high. Pull a sample and test it a few seconds later and it's all good. Funny thing is my bluelab doesn't seem to have that issue.


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## quarantine_grower (Feb 27, 2021)

fragileassassin said:


> It was a literal comment you fucking cuck.
> You arent going to bring people back from the dead. youve seen how active this post has been since youdug it up from the grave. Most ppl see the date and skip it.


Hi, it’s 2021 and yes, you are the dick on this thread. This thread just answered a question i had.


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