90F Rez Temps No Problem

[Voltrom]

So I happened to stumble upon this video.

[video=youtube;oocuBknEtEA]

[/video]

Fizzy Farm DWC Review | Taking Oxygen To The Next Level | Outdoor Hydro

Basically a Venturi Pump in a tub with water and nutes. But can this be?

"The plants do just as good in 90 degree weather as they do in an airstone fed DWC operating at perfect 68 degree weather. And this applies to indoor growers as well"

This unit is supposedly the best system and is designed for outdoors.

Wait a second... Outdoors??! Obviously in California my water temp would be a simmering 90F at least. But yet this system can take away my fear of high temps. ? I'm currently using two airstones right now. I have a Venturi pump that would be perfect for my 10gal cooler but it makes the water too hot. So I figured... I know Venturi pumps are far superior in terms of aeration. It actually moves all the water constantly and that in itself keeps the water fresher. Air stones just agitate the surface. But fail when temps swing becuase it's only surface agitation...



Can Venturi be the miracle? If I move my water will this somehow take away the dangers of high temp. ?? This can't be true but it makes sense now that I think about it. Bubbles are one thing but circulating your water is a whole different ball park..

Comments?

 

[oldman60]

Re: 90F Rez Temps No Problem.

It doesn't take a lot of agitation to saturate water with dissolved oxygen. Saturated warm water has less dissolved
oxygen than saturated cold water.

Once water is saturated more agitation will not increase the dissolved oxygen.

 

[GreatLife4All]

Re: 90F Rez Temps No Problem.

Full of hype. Indoor vs outdoors is an unmimportant distinction.

I have grown lots of lettuce and herbs down in my basement using aeroponics. I always get better roots than he is showing. Growth rates are amazing. And lettuce won't grow well in 90 degree air temperatures - independent of the temps in the reservoir. So that was just a bunch of BS.

He is not taking into account the growth rate of bad bacteria and fungus - they grow best when oxygen levels are low and temperatures are high. And that is EXACTLY what he is advocating. You are going to have to use chemicals / treatments to keep the bacteria and fungus levels low. Root rot is not fun to deal with...

And it does not matter how or why the oxygen is dumped into the water. Physics states that the dissolved oxygen level of the water is tied directly to the temperature of the water. It is also the case that as heat goes up - transpiration increases in the plant. What does this mean? As ambient air temperatures increase, plants have to take up more water from the roots, at a time when the roots are restricted in their uptake by the temperature-reduced dissolved oxygen levels.

However, using a venturi to inject air without an airstone will certainly work. I have tested a pump which had one of these connections - and it worked fine. i didn't see any advantage to running this though... and I don't want to lose both my air pumps and water pump at the same time. In a DWC system, the plants will die quickly in stagnant water.

It would be very interesting to see if anyone can defend this system...

 

[OutdoorHydro]

Re: 90F Rez Temps No Problem.

Hey all, I am the guy in this video so I thought i'd elaborate a little more as I think there are some misunderstandings going on in this thread.

This lettuce was grown in high 80's temps, and the guy who makes these units is in Orlando Florida and he grows great in 95+ weather with high humidity. I didn't think it was going to work as well as advertised at first, but it certainly does.

And lettuce won't grow well in 90 degree air temperatures - independent of the temps in the reservoir. So that was just a bunch of BS.

Again, the lettuce pictured in the video was grown at almost 90 degrees, however it was of course not in direct sunlight (this was grown with a cheap T5 light).

He is not taking into account the growth rate of bad bacteria and fungus - they grow best when oxygen levels are low and temperatures are high. And that is EXACTLY what he is advocating.

No actually I was advocating high oxygen content levels, not low ones as you describe. And fungus has yet to be an issue with this system. Keeping the water ultra aerated seems to work wonders against bacteria, at least that's been my experience thusfar.

You are going to have to use chemicals / treatments to keep the bacteria and fungus levels low. Root rot is not fun to deal with...

Have not had to do this yet with this system and I've grown several crops at this point. It's really no different than any other DWC in terms of fungi/algae, and if anything it's harder for them to grow because the water is so damn turbulent.

And it does not matter how or why the oxygen is dumped into the water. Physics states that the dissolved oxygen level of the water is tied directly to the temperature of the water.

Could you elaborate on what physics principles you are referring to? Because dissolved oxygen content can change independently of temperature, though the two are tied together if there are no external influences obviously.

For example, here are the D/O readings on water from this unit:

Personally the reason I like this system more than my other various DWC systems is because the manufacturer chose the best venturi pump for the size of the rez. Usually venturi pumps generate a lot of heat, but this one doesn't seem to do that. It honestly works amazing and I get great growth in it, it is at least as good as any other DWC I've tried (though in my opinion it's better, but everyone has their own style).

Plus there's a cool wood enclosure that makes it look a little bit nicer if you're into that sort of thing:

And in response to this:

It doesn't take a lot of agitation to saturate water with dissolved oxygen. Saturated warm water has less dissolved
oxygen than saturated cold water.

Once water is saturated more agitation will not increase the dissolved oxygen.

But it will maintain the higher level of dissolved oxygen at higher temps better than an airstone alone, because normally the hotter the water the less oxygen it wants to carry, but here it just constantly saturates the water with oxygen, whereas a traditional airstone isn't going to be as effective at high temps because it isn't very vigorous.

Here is a quote from Environmental and Experimental Botany 57 (2006):
"In classical hydroponics, a boundary layer develops around the active absorbing regions of the root, modifying apparent uptake kinetics of even the most mobile ions (Weathers and Zobel, 1992). Hydroponics with vigorous aeration, thin film (nutrient film technique, NFT) hydroponics and aeroponics, obviate this problem, giving the root immediate access to even the least mobile ions."

So there is definitely some evidence that "vigorous aeration" is superior to just the small bubbles from an airstone. In my personal experience I've found that to be true anyways, more oxygen=better.

 

[OutdoorHydro]

Re: 90F Rez Temps No Problem.

Wait a second... Outdoors??! Obviously in California my water temp would be a simmering 90F at least. But yet this system can take away my fear of high temps. ?

For what it's worth, i'm in California and I made the video, and the plants grew great despite how fucking hot it gets in that garage lol. I normally could never grow lettuce in there because it was just too damn hot, but with this system it did great. I've been using it indoors in my garage ever since, as the garage tends to get even hotter than it is outside.

Indoor vs outdoor is an important distinction, there is a lot more you have to account for outdoors. Rain for example, meaning all your shit needs to be waterproofed. One of the advantages here is that since the pump is waterproof you don't have to worry about getting water on it. I can't tell you how many of those airstone pumps i've had to buy because they got wet or something, so this one is cool because it's fire and forget, you don't have to babysit it every time it starts drizzling outside. Now if it's pouring your rez is gonna overflow but that's unavoidable, at least it will survive the CA drizzles that we get up here in Norcal.

 

[Voltrom]

Re: 90F Rez Temps No Problem.

As of today I've added a Venturi to my system,, a flooming affect. Pushing the water upwards and out. I've combined this with my airdromes as well. If what you say is correct and what my research shows,, this will solve the thousands of people with high temp problems. The fact is air stones alone provide enough oxygen but when high temps occur the stagnant water that isn't directly stimulated by air slowly allows bacteria to form. I used to think high temps DIRECTLY affect root growth. (Root rot) but now I know that high temps take away the oxygen CAUSING root rot. So now I have super agitated water and I'm so done with these frozen water bottles.

I think everyone needs to know about how inefficient air stones are.

-Voltromik

 

[OutdoorHydro]

Re: 90F Rez Temps No Problem.

As of today I've added a Venturi to my system,, a flooming affect. Pushing the water upwards and out. I've combined this with my airdromes as well. If what you say is correct and what my research shows,, this will solve the thousands of people with high temp problems. The fact is air stones alone provide enough oxygen but when high temps occur the stagnant water that isn't directly stimulated by air slowly allows bacteria to form. I used to think high temps DIRECTLY affect root growth. (Root rot) but now I know that high temps take away the oxygen CAUSING root rot. So now I have super agitated water and I'm so done with these frozen water bottles.

I think everyone needs to know about how inefficient air stones are.

-Voltromik

I have come to the same realization. I'm not even using airstones any more as temperatures in my area were too much of a problem. Now that I'm using the venturi pumps it's no longer an issue. Note that they don't scale well though, I have one system with a 55 gallon reservoir and that is too large for a venturi system unless I can find a custom made pump (working on it though!).

You have to keep in mind that an air bubble can only saturate during the time that it is in contact with the nutrient. When you shoot nutrient at a high speed than you can keep that same bubble in contact with the water way longer.

Let me know how the venturi pump works for you, I've only known about 5 people who converted and everyone seems to be of the same opinion regarding its better performance at high temps. Would love to hear some validation from someone I wasn't already friends with. And enjoy not having to constantly fill bottles with ice any more.

 

[oldman60]

Re: 90F Rez Temps No Problem.

Amazing someone hasn't discovered this in all the decades of hydroponics until now.

 

[OutdoorHydro]

Re: 90F Rez Temps No Problem.

Amazing someone hasn't discovered this in all the decades of hydroponics until now.

Well it isn't anything new really. There's been a few white papers on the subject in the past, I'll try to find them.

A quick Google search shows a few papers and articles on why dissolved oxygen is so important (listed below). Using a venturi pump is just one way of accomplishing higher D/O levels, but I'm sure there are others.

Redirect Notice

 

[oldman60]

Re: 90F Rez Temps No Problem.

LOL having spent a lifetime in the petro-chemical field I have a good grasp on DO, COD, BOD and their relation to water.

Like I said before once the water has all of the dissolved oxygen that it can hold at a given temp no amount of
added agitation will increase it. A good pump and air stone will turn the water over more than enough.

The previous post was more a joke than anything else. I wasn't referring to dissolved oxygen I was
referring to your discovery that very high temps don't matter.

 

[DedoVerde619]

Hey fellows, I'm new to growing period but I'm going with a DWC. So instead of using a airstone w/ air pump use a venturi pump?

Somewhere

 

[OutdoorHydro]

Re: 90F Rez Temps No Problem.

LOL having spent a lifetime in the petro-chemical field I have a good grasp on DO, COD, BOD and their relation to water.

Like I said before once the water has all of the dissolved oxygen that it can hold at a given temp no amount of
added agitation will increase it. A good pump and air stone will turn the water over more than enough.

The previous post was more a joke than anything else. I wasn't referring to dissolved oxygen I was
referring to your discovery that very high temps don't matter.

I'm not saying high temps don't matter, I'm saying that the effects of high temps on water can be combated by more aggressively aerating it vs. Just blowing bubbles into it.

Let me find the papers on this, there is quite a bit of evidence that airstones are not as effective as is commonly believed.

Not sure what part of the petrochemical industry you are in, but my wife is a lead chemist for a defense contractor and I would be more than happy to have her perform a Winkler titration DO test on warm water that is heavily aerated if you don't believe me. It is absolutely possible to keep the DO at a usable amount even in 80 or 90 degree weather. Again, the lettuce shown was all grown in these temps, and you know how picky lettuce is about heat.

 

[OutdoorHydro]

Re: 90F Rez Temps No Problem.

Hey fellows, I'm new to growing period but I'm going with a DWC. So instead of using a airstone w/ air pump use a venturi pump?

Somewhere

Honestly airstones are going to be fine in 99% of hydro applications. For me the venturi pump works better because I grow outside in the heat but if you are new I would just get two airstones.

 

[DedoVerde619]

Honestly airstones are going to be fine in 99% of hydro applications. For me the venturi pump works better because I grow outside in the heat but if you are new I would just get two airstones.

Ohh, so indoors it's ok with airstones but outside a venturi pump with hot weather would be better ok. Thanks for the reply buddy..

Somewhere

 

[OutdoorHydro]

Re: 90F Rez Temps No Problem.

Ohh, so indoors it's ok with airstones but outside a venturi pump with hot weather would be better ok. Thanks for the reply buddy..

Somewhere

Depends on your temp indoors I suppose. I would just go with airstones and see how that works. I do most of mine with airstones except the DWC I was describing above because it's in my garage which gets ludicrously hot during the summer.

 

[Voltrom]

Re: 90F Rez Temps No Problem.

Yes of course airstones will work but when your temp goes beyond 70 and well into the mid 80s that's when a venturi will STILL be agitating the water enough to maintain the DO.

Honestly this is one of the most amazing things to me becuase now I don't ever have to worry about temps. This and the fact that I just added a 7200k to my grow room making it dual spectrum are gonna just make my plant explode...


People must know about this. That instead of a chiller you can just find a way to agitate the water more thus solving your problem.

 

[Voltrom]

Re: 90F Rez Temps No Problem.

The fact that a Venturi will solve any resevoir temp problems should be the FIRST thing someone knows when they build their dwc unit.

 

[OutdoorHydro]

Re: 90F Rez Temps No Problem.

Oh yah I agree. It took me about a year before I figured this out. I have a $300 chiller for my larger ebb & flow system and wasn't about to spend that again for an indoor DWC, this pretty much solves the whole problem.

For anyone not believing this, go buy or make a venturi pump and see for yourself, it isn't even that expensive. Way worth it imo.

 

[oldman60]

Re: 90F Rez Temps No Problem.

"I'm not saying high temps don't matter, I'm saying that the effects of high temps on water can be combated by more aggressively aerating it vs. Just blowing bubbles into it."

Well I was going by the the thread Title.

I agree you can successfully grow with high res temps, just not as well.
I am dealing with high temps right now as I do with every summer grow. While the res temp isn't in the 90s it
is in the low 80s in heat of the day and the air stones in each bucket are moving the water more than enough to
saturate it with DO. My winter grows under the exact same conditions except temps alway produce better.

FYI the bubbles you see is not dissolving directly into the water. They make the water move and that movement at the
surface is where the molecular exchange takes place.

 

[OutdoorHydro]

Re: 90F Rez Temps No Problem.

FYI the bubbles you see is not dissolving directly into the water. They make the water move and that movement at the
surface is where the molecular exchange takes place.

Exactly, like I said before, the venturi method of aeration does a better job of breaking the surface tension of the water which is, as you stated, what aerates it. Therefore the more the surface tension is broken, the more oxygen gets into the water.

I will agree that no matter what, colder water (ideally 68 degrees) is always better than warm water regardless of how you are aerating it. But for some people, like myself, I couldn't grow anything in high 80's temps with airstones alone so I figured i'd pass along my experience of what worked in my use case.