RO vs Distilled

[swwilson20]

I was curious to see the difference in ph levels in my distilled and RO water. (Distilled water came from 1 Gal store bought jug, RO came from a fill station where you take your empty bottles) So I tested both and Distilled sits at around 6.3-6.4 and the RO water clocked in at 7.0. My plants are 2 weeks old and all feedings except the last one, were done with Brita filtered water, and ph for that water was 6.0-6.2. I haven't started feeding any nutes. I do not have PH up or down at the moment and I MUST water all of them before I can get to the grow shop or have anything shipped. I'm somewhat stumped here because both of my sources are close to the edge of being too low or high.. And I've been using around 6.0 water this whole time, so my intstinct tells me use RO water at 7.0, but I certainly don't know for sure. Or could I mix them? I don't know, can somebody help me out??

 

[Major PITA]

Our distilled water comes in at exactly 7.0. Have you calibrated your meter recently?
What are you growing in - soil, hydro, ???

 

[swwilson20]

Its brand new and says its been calibrated. I'm growing in soil. It is a Milwaukee ph 80 I believe

 

[Major PITA]

Most soil is pretty well buffered. I'm going out on a limb and say it doesn't matter which you use. In theory the lower PH would be better, but I wouldn't sweat it. I use plain tap water and believe the trace minerals are better than using distilled or RO. However, we have "good" water. I never adjust the PH of it for soil grows. I use it as-is at 7.0 to 7.1 PH throughout a grow.

 

[Fuzzy Duck]

As Major said soil is pretty self buffering providing it has PH range is between PH 6 & 7 you should be fine. the only time it may increase towards an acidic nature is more likely during flowering with an increase of nutrients used & possible build up of salts.


I've been growing in soil for a while now & never bothered with PH correcting the water or nutrients to which i do just fine.


If ya not sure about that idea just ask your self how do people feed or water house plants, veggies or plants grown in the back garden or even farmers irrigating their fields, i'm pretty sure that is not PH corrected.

Even rain fall has a PH value & i'm sure that is not perfect either.

 

[MassMedMan]

It's tough to get an accurate reading of ph with RO water. I only test when using certain nutes and that's after the main nutes or before additives. I'd use RO unless you know you have good water. If so, tap is easy and cheap just leave it out 48 hours. I went to RO this summer and don't regret it, well, I wish I got a bigger system. But, for peace of mind, well worth it. Good luck.

 

[Icemud]

I may be incorrect but I think I remember that when dealing with R/O and distilled water, since the ppm is virtually null, water of this purity will tend to gain acidity over time as it absorbed CO2 from the air. I believe that the absorption of CO2 creates carbonic acids in the water which free up H+ molecules and lowers the PH. From a quick few searches it seems that pure water that reaches equilibrium with the air will have a general PH around 5.65 but this also has to do with CO2 concentrations in the air, and this is part of the same reason for increased CO2 emissions in the air and acidic rain

Measuring R/O and distilled water with a PH meter is tough because pure water typically lacks conductivity in which PH meters use to take readings by generating an electrical current over the probes.

 

[fanleaf]

I may be incorrect but I think I remember that when dealing with R/O and distilled water, since the ppm is virtually null, water of this purity will tend to gain acidity over time as it absorbed CO2 from the air. I believe that the absorption of CO2 creates carbonic acids in the water which free up H+ molecules and lowers the PH. From a quick few searches it seems that pure water that reaches equilibrium with the air will have a general PH around 5.65 but this also has to do with CO2 concentrations in the air, and this is part of the same reason for increased CO2 emissions in the air and acidic rain

Measuring R/O and distilled water with a PH meter is tough because pure water typically lacks conductivity in which PH meters use to take readings by generating an electrical current over the probes.

You are correct. Both Distilled and RODI or RO will show anywhere from 6.0-7.0. Since they really have next to nothing in them you could take a gallon of 7.0 distilled and put just a half drop of ph down in it and the pH will then read way way low because now theres actually something in the water to read.

I used to buy Distilled from one store that always showed up about 7.0 and the same brand from another branch would come in at 6.2. It never matters either way. That was before I upgraded and got my own RODI unit.

 

[fanleaf]

I was curious to see the difference in ph levels in my distilled and RO water. (Distilled water came from 1 Gal store bought jug, RO came from a fill station where you take your empty bottles) So I tested both and Distilled sits at around 6.3-6.4 and the RO water clocked in at 7.0. My plants are 2 weeks old and all feedings except the last one, were done with Brita filtered water, and ph for that water was 6.0-6.2. I haven't started feeding any nutes. I do not have PH up or down at the moment and I MUST water all of them before I can get to the grow shop or have anything shipped. I'm somewhat stumped here because both of my sources are close to the edge of being too low or high.. And I've been using around 6.0 water this whole time, so my intstinct tells me use RO water at 7.0, but I certainly don't know for sure. Or could I mix them? I don't know, can somebody help me out??

If you are just watering without nutes and using distilled or ro water NEVER NEVER NEVER pH your water. All you are doing at that point is adding salts to the soil very unnecessarily. Weather your distilled or ro comes in at 6.0 or 7.0 does not matter one single bit because theres nothing in the water at all and pH'ing it is truly a waste of time/money and salts.

If you are using tap or other water then yes, pH away.

 

[swwilson20]

Thanks guys. I'm glad I can come here before I make a mistake that kills all that hard work and love. I keep reading about how important pH is and the fact that my soil has some things added to it nute wise, so I'm also curious about the pH of my runoff but I've also read those meters aren't that trustworthy and if you use the correct ph'ed water that runoff should be good. I am using Roots Organics soil and it has peat moss, bat guano, fish bone meal, and several other things. Ive heard good and bad things about starting seedlings with nutes of any kind especially with non-organic nutes, but the grow shop honcho had a good sales pitch I guess because he really does make me feel like he wants whats best for my plant. That's the reason why I'm going with Roots Organics. I just can't find a lot of things about it.

 

[MassMedMan]

Thanks guys. I'm glad I can come here before I make a mistake that kills all that hard work and love. I keep reading about how important pH is and the fact that my soil has some things added to it nute wise, so I'm also curious about the pH of my runoff but I've also read those meters aren't that trustworthy and if you use the correct ph'ed water that runoff should be good. I am using Roots Organics soil and it has peat moss, bat guano, fish bone meal, and several other things. Ive heard good and bad things about starting seedlings with nutes of any kind especially with non-organic nutes, but the grow shop honcho had a good sales pitch I guess because he really does make me feel like he wants whats best for my plant. That's the reason why I'm going with Roots Organics. I just can't find a lot of things about it.

Allot of guys used roots four years. not the worst you could do. I used it, but, in the mix I ran it was 20%. I went ffof 60, roots 20, ancient forest 20, and the perlite by 10% of my mix. I didn't cook that, dropped seeds and went and did ok.

In researching roots years ago I stumbled on an article or chat room that talked about a high bug content, I treat my water/soil with mosquito bits and have never seen any issues like that.

Good luck

 

[swwilson20]

That's interesting Med Man bc I within 48 hours of watering new pots I started seeing fungus gnats. Not even 48hrs honestly . I think they hitched a ride in the bag of soil I'm using. Using Mosquito Dunks but they haven't started working yet but it's only been a week since I started using it. Fingers crossed. Thank you for chiming in about Roots Organics Med Man

 

[MassMedMan]

That's interesting Med Man bc I within 48 hours of watering new pots I started seeing fungus gnats. Not even 48hrs honestly . I think they hitched a ride in the bag of soil I'm using. Using Mosquito Dunks but they haven't started working yet but it's only been a week since I started using it. Fingers crossed. Thank you for chiming in about Roots Organics Med Man

I'd still use it, but I run doc's. The bits will take care of those knats in no time. Good luck!