Reverse Osmosis and growing cannabis (Part 1)

[Josh]

Water will become more stable as you add more nutrients because this increases the buffering capacity. Calcium Carbonate had a high buffering capacity so if your water is very hard, it will take a lot of acid to reduce the PH but it will be the most stable and predictable. This question is quite ambiguous though, do you mean stable as in mixing time or stable as in constant as the plants feed? If you mean the latter, that's a completely different subject and if people would like, I could cover that too in another post?
No worries TTL, lockdown got me writing posts :)
Thanks Integrajosh! I'm not sure if it's different across the water but in the UK and within the hobby hydro market, most nutrients come in a hard and soft water variant. I'm pretty sure most nutrients that specify soft water would be suitable for RO in most situations but cannabis does love it's calcium. The trouble is with calcium is it's linked to transpiration! It's quite common in indoor because of the lack of control over HVAC for many cannabis growers as we have to be stealthy and keep things compact. Lack of air movement and hot temperatures can manifest into calcium def. There is actually more to consider like a the relationship between calcium and magnesium and optimal ratios of the two but that's getting a little deep for me. I'm still learning here too so can't explain it all but I've read the optimal ratio is 8:1 Ca to Mg? It would indeed be so much easier for manufacturers if everyonr used RO as you're starting with a blank slate.
Thanks Minty, I actually taught myself to type about a year ago. I've been a computer engineer for nearly 20 years and couldn't type for shit. When I started, I was sitting around 20wpm and looking down. In about 3 months, I was sitting around 40wpm and now I'm hovering around 60-70wpm. Definitely a skill worth learning as when writing larger things, you don't have to think about typing as it's a natural as talking.

Saying all that, I'm on my phone now so that slows me down a bit lol. In regards to DO levels in the water, it's nice to know but far from required. As long as you have good movement of water and keep the temps below 28C, you can confidently say you have plenty :)

In regards to should you use RO water, I'll cover this in more details in part two. The reason why I split the article into two parts is because reverse osmosis is far from required to grow good weed and there's lots of misinformation around that influence peoples decisions. I wanted to make it clear that RO os far from essential and can make things worse if you don't understand RO water and how to use it. But the quick version is RO is like giving a grower the tools to bring out the best in your grows and in the right hands can bring a host of benefits but also has it's downsides and is also handing you a loaded gun for you to shoot yourself in the foot :) As a beginner, I would normally advise against it but judging by the level of detail I've seen you pile into your projects I think you will do well with RO and tripart Minty.
RO water has zero buffer. Again, this is better saved for part 2 but RO is PH neutral but without any buffer, RO water is unstable. When you initially mix up, your water will drop rapidly as it assumes the PH of the bottled nutrients and then you have to bring it up. Once mixed, it's actually quite stable with some very big caveats! As the plants and mocrolife use the nutrients, the PH will change. Saying that, this can be easily buffered by additional additives like humic acid and other agents that will balance things out. PH perfect was at first mistaken for the same thing but it's completely different. How PH perfect works (from memory so correct me if I'm wrong Josh) is it's been formulated for RO water and contains a specific formulation that guarantees that the PH will be the same when mixed at the correct levels and not a buffer to compensate for biological activity in the system. And it doesn't work in hard water :) they have always stated to get the most out of their range, you need to use pure RO water.

Sry bro, but from years of trial and error I gotta disagree with you still. Lmaoo

Cannabis plants aren't calcium whores like tomatoes, I realise that every environment is different and environmental factors can manifest into deficiencies (like you mentioned) but the solution is to fix your environment, not figure out the perfect ratio of cal to mag or switch to RO on a whim

Proper night and day time temps, proper night and day time humidity, good air movement, good air exchange

Also keep in mind that if you supplement co2, this will rapidly lower the ph of a mix using RO water. I switched to tap and the issue is gone, no more ph diving overnight.
I can keep my air pumps in the same room again, which is awesome. 1500 ppm of co2.
Same nutes, same additives, only difference is switching to tap

I realise that some people have crazy water, like yourself, but like you said for 99% of growers it's unnecessary nd causes issues

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Thanks for the feedback Josh! It's good to disagree and hear others experiences. I'm not saying you can push the TDS up to the levels tomatoes can gobble up but cannabis ain't no slouch when it comes to gobbling up the calcium.

I also think that the levels don't have to be as accurate as people think. My feelings are the plant will take what it requires as long as it has enough reserve. Ratios and absence are more important if we're talking about nutrient formulas.

The reason why you see a drop in your PH when using CO2 with RO and airstones is your airstones are pushing CO2 into the water and that reacts with the water and creates weak carbonic acid (H2CO3). The reason why this doesn't affect you so much with tap water is you have more calcium carbonate to buffer the reaction. Calcium carbonate is a very good buffer. :) don't use airstones with RO :)

Dude, I added a shitload of buffers to my RO water. Lmaooo
Yet it still dropped

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[seymore_budz]

Sry bro, but from years of trial and error I gotta disagree with you still. Lmaoo

Cannabis plants aren't calcium whores like tomatoes, I realise that every environment is different and environmental factors can manifest into deficiencies (like you mentioned) but the solution is to fix your environment, not figure out the perfect ratio of cal to mag or switch to RO on a whim

Proper night and day time temps, proper night and day time humidity, good air movement, good air exchange

Also keep in mind that if you supplement co2, this will rapidly lower the ph of a mix using RO water. I switched to tap and the issue is gone, no more ph diving overnight.
I can keep my air pumps in the same room again, which is awesome. 1500 ppm of co2.
Same nutes, same additives, only difference is switching to tap

I realise that some people have crazy water, like yourself, but like you said for 99% of growers it's unnecessary nd causes issues

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Thanks for the feedback Josh! It's good to disagree and hear others experiences. I'm not saying you can push the TDS up to the levels tomatoes can gobble up but cannabis ain't no slouch when it comes to gobbling up the calcium.

I also think that the levels don't have to be as accurate as people think. My feelings are the plant will take what it requires as long as it has enough reserve. Ratios and absence are more important if we're talking about nutrient formulas.

The reason why you see a drop in your PH when using CO2 with RO and airstones is your airstones are pushing CO2 into the water and that reacts with the water and creates weak carbonic acid (H2CO3). The reason why this doesn't affect you so much with tap water is you have more calcium carbonate to buffer the reaction. Calcium carbonate is a very good buffer. :) don't use airstones with RO :)

What's the point of this thread bro? You trying to convince people to use RO, not use it, or just have a discussion about water in general?
I'm confused

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The point of the thread is to share knowledge and experiences. I don't want to convince anyone to do anything. You do you buddy! The co2 dropping the PH is a well known side effect of using airstones in RO and can be explained with chemistry. What did you use as a buffer. Adding buffer is quite ambiguous as lots of things can act as a buffer and each has a different buffering capacity.

[Josh]

Thanks for the feedback Josh! It's good to disagree and hear others experiences. I'm not saying you can push the TDS up to the levels tomatoes can gobble up but cannabis ain't no slouch when it comes to gobbling up the calcium.

I also think that the levels don't have to be as accurate as people think. My feelings are the plant will take what it requires as long as it has enough reserve. Ratios and absence are more important if we're talking about nutrient formulas.

The reason why you see a drop in your PH when using CO2 with RO and airstones is your airstones are pushing CO2 into the water and that reacts with the water and creates weak carbonic acid (H2CO3). The reason why this doesn't affect you so much with tap water is you have more calcium carbonate to buffer the reaction. Calcium carbonate is a very good buffer. :) don't use airstones with RO :)

What's the point of this thread bro? You trying to convince people to use RO, not use it, or just have a discussion about water in general?
I'm confused

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The point of the thread is to share knowledge and experiences. I don't want to convince anyone to do anything. You do you buddy! The co2 dropping the PH is a well known side effect of using airstones in RO and can be explained with chemistry. What did you use as a buffer. Adding buffer is quite ambiguous as lots of things can act as a buffer and each has a different buffering capacity.

I used the unicorn dust and flux capacitor juice from GH for my buffers, did I do it wrong?

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[seymore_budz]

What's the point of this thread bro? You trying to convince people to use RO, not use it, or just have a discussion about water in general?
I'm confused

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The point of the thread is to share knowledge and experiences. I don't want to convince anyone to do anything. You do you buddy! The co2 dropping the PH is a well known side effect of using airstones in RO and can be explained with chemistry. What did you use as a buffer. Adding buffer is quite ambiguous as lots of things can act as a buffer and each has a different buffering capacity.

I used the unicorn dust and flux capacitor juice from GH for my buffers, did I do it wrong?

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Lol like I said, you do you buddy :) look up PH and pka for buffers and the henderson-hasselbalch equation. Don't get stressed out Josh! I'm just giving my opinion. Apologies if I upset you.

[Josh]

The point of the thread is to share knowledge and experiences. I don't want to convince anyone to do anything. You do you buddy! The co2 dropping the PH is a well known side effect of using airstones in RO and can be explained with chemistry. What did you use as a buffer. Adding buffer is quite ambiguous as lots of things can act as a buffer and each has a different buffering capacity.

I used the unicorn dust and flux capacitor juice from GH for my buffers, did I do it wrong?

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Lol like I said, you do you buddy :) look up PH and pka for buffers and the henderson-hasselbalch equation. Don't get stressed out Josh! I'm just giving my opinion. Apologies if I upset you.

Does it sound like I'm upset through text? This is a good bit of fun buddy, no offense taken at all

I'm a self proclaimed comedian/asshole, don't take me too seriously

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[seymore_budz]

I used the unicorn dust and flux capacitor juice from GH for my buffers, did I do it wrong?

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Lol like I said, you do you buddy :) look up PH and pka for buffers and the henderson-hasselbalch equation. Don't get stressed out Josh! I'm just giving my opinion. Apologies if I upset you.

Does it sound like I'm upset through text? This is a good bit of fun buddy, no offense taken at all

I'm a self proclaimed comedian/asshole, don't take me too seriously

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Hahaha yes mate it did sound like you were getting a little salty :) Wait for part 2 before you roast me fully.

[seymore_budz]

And I'm still interested in what you added as a buffer!!

[Josh]

My apologies though, for real. Don't get me wrong, I love this topic bro!
Mainly because it's a never ending debate, lmao

On one side with RO, you start with perfectly clean water. Fantastic! Now we just add back in a bunch of stuff that we took out, and viola! A perfectly tuned recipe for our plants, with nothing that they don't need in the water
sarcasm

See where I'm going with this?
You are 1000% correct though, some households NEED RO water
Let's not even talk about Flint, Michigan

Just hear me out on this though-

With affordable units, it takes 8-10 gallons of tap to make 1 gallon of RO (I'm sure pricy ones are more effiecient)
If you're paying for water, I think this is already a deal breaker unless you absolutely NEED it

I'm like you in the sense that I want to do everything possible to maximise the grow. But with plants, I just don't feel like RO makes a difference unless your tap is insane.
My shower turns orange every month from buildup but the plants are fine

These days I look to maximise output with minimal input, and I feel RO just isn't in line with that





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[Josh]

And I'm still interested in what you added as a buffer!!

200-250ppm calimagic, silicate, base nutes and fulvic acid

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[seymore_budz]

My apologies though, for real. Don't get me wrong, I love this topic bro!
Mainly because it's a never ending debate, lmao

On one side with RO, you start with perfectly clean water. Fantastic! Now we just add back in a bunch of stuff that we took out, and viola! A perfectly tuned recipe for our plants, with nothing that they don't need in the water
sarcasm

See where I'm going with this?
You are 1000% correct though, some households NEED RO water
Let's not even talk about Flint, Michigan

Just hear me out on this though-

With affordable units, it takes 8-10 gallons of tap to make 1 gallon of RO (I'm sure pricy ones are more effiecient)
If you're paying for water, I think this is already a deal breaker unless you absolutely NEED it

I'm like you in the sense that I want to do everything possible to maximise the grow. But with plants, I just don't feel like RO makes a difference unless your tap is insane.
My shower turns orange every month from buildup but the plants are fine

These days I look to maximise output with minimal input, and I feel RO just isn't in line with that





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Dude!!!! We are on the exact same page! This is what I'm saying in this write-up :) but...... I think there is benefits to using RO. And I'll go into that in part 2. Your point about putting back what we took out, kind of true when we're talking salts but there are other things RO removes but cost over return, you got me there :) you're not going to see 30% bigger returns or even 5%. You may notice small nuances but nothing to get excited about. Your tap water grown weed is just as good as my RO grown weed. This is why I said wait for part two :) I don't want to ruin it by going into it too deep here and I want to give RO a fair trial. This post was the prosecution and part 2 will be the defense. But, the reason why I use RO is to stop the fooking limescale buildup. My tap water can glue a dinner plate to a table :) you would only use RO to solve an issue. If you don't have an issue, you're breaking thr KISS rules.

Right that is interesting. Calimagic is indeed derived from calcium carbonate. When you say PPM, what scale?