New Grower What are your thoughts on RO Water?

[A4]

Let me preface this by giving my reason for asking this question. I have been growing for some time, always using Promix and GH Nutes. The same system, the same feed schedule, same lighting schedule, same temps, everything is exactly the same. I have used carbon filtered tap water from the beginning. So, one of my first Auto grows on here I was reading about RO water. I have a place down the road that sells RO so I stopped in and picked up 2 5 gallon bottles to give it a try. No reason in particular, I just thought it would be worth trying. So, I put the water in my 15 gallon stainless pot to aerate for a few days and let the water temp get to the grow room tent. Basically the same thing I do with my tap water. So, I feed the plants with the RO and days later I am seeing Zinc deficiencies. I mean classic zinc deficiency with no warning at all. So, I dump the RO go back to the tap and have never had that problem again. Ever. Now, Sunday(2 days ago) I am at the store and see the RO sitting there laughing at me. I am thinking, there is no way that the RO caused that problem. I have read too many people running RO with no problems and everything is wonderful. So I buy 2 more 5 gallon bottles. I come home and it is feeding day so I put the water in my tank to bubble for a few hours and later that night I go back to feed. Same feed schedule, same everything except now I am using the RO water. I check my plants probably 6 times a day. So, I go out there today when I get home from work and pull them out to water them and you probably guessed by now, zinc deficiency. Banded leaves, new young leaves very thin and yellow.
WTH? Has anyone seen problems like this out of RO water? I am beginning to think the RO has a different charge and is stripping certain minerals completely out of my grow media. Eagerly awaiting to hear your thoughts on this.

 

[GoAuto6]

The thing about RO is there are no trace minerals in it... If you ask me if your tap water does not have potasiumcloride in it ( I think it is) then letting your tap water evap the clorine out is better suited because it still has the trace minerals....

 

[GoAuto6]

Hey PIG what do you think......

 

[A4]

I agree GA6, I am pretty much done with RO but I really want to see some hard evidence of what is causing the deficiency. This was one feeding, just one. I can't believe the RO caused a problem that quick? There are too many people using it. I am hoping some old hand chimes in with similar circumstances or a reason behind what happened.

 

[GoAuto6]

one watering thats f-in fast.....mmmm hope piggy chimes in.

 

[WVTurtle]

Thats very strange indeed. Espcecially to show up that quick. I have been using RO water from day one for my auto grows without any issues.

 

[A4]

No kidding it is, dude the grow journal is in the live fert section. I have been documenting everything, I mean everything with this grow because I am about to switch nutes for the first time ever. I was sick to my stomach when I pulled them out tonight. Literally sick to my stomach.

 

[A4]

Thats very strange indeed. Espcecially to show up that quick. I have been using RO water from day one for my auto grows without any issues.

And that is where my thinking is going with this problem. I am beginning to think if used from the start of the grow then the plants will adapt to the amount in the media and only take up what they need because they know it is there. But when switching in mid grow, maybe it somehow shocks the plant or possibly the minerals that are in the media isn't binding with to RO? I am perplexed.

 

[Muddy]

Are you sure it wasn't a mg deficiency and not iron? Both can look very similar. Yellowing is usually mg, more white if it's iron. In a case like this I would expect mg would be more likely. As Goauto mentioned, it's the lack of minerals in the RO water. Hydro grows often experience this when using RO. Add some cal/mag and that should take care of it, or mix in 25% tap water to the RO.

 

[A4]

Zinc Muddy, it was the banded leaves. Classic zinc, looked just like a snake, only at the top of the plant on new growth. All older growth still looked perfect. I had added an extra 10ml/gallon of Cal/Mag when I used the RO because I was worried about not getting it from my tap. I don't have my pictures here with me but will put one up when I get home.