Idea for keeping reservoir temps cool

[^Slanty]

facestabber, thats my thing, also. we need some root porn.

Will this do?
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[facestabber]

yup, those are some good ones.

 

[^Slanty]

As to the OP's question. The cheapest way to cool your res is by running a geothermal coil/loop. Always the same temperature. Requires a bit of work to install, but if you are doing it for the long haul, then it is by far the cheapest!

 

[waterdawg]

Buy a used dehumidifier (got mine almost new for $50), $8 water pump, and a $40-50 ss wort chiller. Pull the evaporative cooling coils/radiator out of the dehu unit, place it into a plain water reservoir. Pump nutrient solution through the wort chiller in the cooled res and back. Put the dehu on a timer or thermostat.

Jeez I would love to see the pics! I'm not sure what a wort chiller is BTW. I would love to make one as I will certainly be shutting down when spring arrives due to temps. Also that funky smell coming from the res, perhaps it's a bad thing!!!!

 

[mike91sr]

Nope, don't keep my roots in my rez......lol. At 86F there is almost ZERO dissolved oxygen in water. Cannabis roots would most certainly die if submerged in 86F water for long.
BTW, NO ONE makes roots thrive better than me, it's my "thing".

Youre right about the low DO, but a plant isn't going to suffocate just because the water can't dissolve as much oxygen. Heres why.. No matter how much or how little oxygen is dissolved in water, its irrelevant if you provide enough oxygen to the roots themselves. In DWC, all you have to do is make sure theres constantly enough aeration(very easy) that the plants never need to even try use the dissolved oxygen. Oxygen is much more prevalent in the atmosphere than ANY level of DO normally seens in hydroponics. So provide more atmospheric oxygen via more bubbles, and there's never any need to concern yourself with how much or how little is being dissolved.

Think about it..Aeroponics systems work so well because roots are exposed to atmospheric oxygen constantly, again DO has nothing to do with it. If DO mattered, you'd have to dissolve oxygen into the water before spraying your plants with it so they could breathe. We can agree thats completely untrue, correct?

Compare it to canopy temp too. Whats the biggest benefit we see from increasing temperatures? Increased metabolism/photosynthesis. Though roots are performing different functions, their cellular functions are increased as temperature increases(obviously finitely). There's really nothing I know of in the physical world that slows down by increasing temperature, and that includes both plants and animals.

 

[mike91sr]

Jeez I would love to see the pics! I'm not sure what a wort chiller is BTW. I would love to make one as I will certainly be shutting down when spring arrives due to temps. Also that funky smell coming from the res, perhaps it's a bad thing!!!!

A wort chiller is a coil of ss or copper that chills a wort for brewing beer. Basically a tube that provides a high surface area to allow heat transfer. No pics of my setup, sorry. Heres a diagram. Instead of pumping the chilled water in/out like the diagram shows though, keep it contained and drop the wort in it.





btw, I dont get that smell as long as my temps are down. Even when they're mid/high-70s, it takes a few days to a week to start smelling it, and I've been forced to have my temps up there for a few weeks before without problems, just prefer not to. I also don't run a sterile res most of the time, I treat a fresh res with bleach or h2o2, then add bennie tea a few days later after its dissipated.

 

[facestabber]

Youre right about the low DO, but a plant isn't going to suffocate just because the water can't dissolve as much oxygen. Heres why.. No matter how much or how little oxygen is dissolved in water, its irrelevant if you provide enough oxygen to the roots themselves. In DWC, all you have to do is make sure theres constantly enough aeration(very easy) that the plants never need to even try use the dissolved oxygen. Oxygen is much more prevalent in the atmosphere than ANY level of DO normally seens in hydroponics. So provide more atmospheric oxygen via more bubbles, and there's never any need to concern yourself with how much or how little is being dissolved.


Think about it..Aeroponics systems work so well because roots are exposed to atmospheric oxygen constantly, again DO has nothing to do with it. If DO mattered, you'd have to dissolve oxygen into the water before spraying your plants with it so they could breathe
. We can agree thats completely untrue, correct?

Compare it to canopy temp too. Whats the biggest benefit we see from increasing temperatures? Increased metabolism/photosynthesis. Though roots are performing different functions, their cellular functions are increased as temperature increases(obviously finitely). There's really nothing I know of in the physical world that slows down by increasing temperature, and that includes both plants and animals.

With the addition of airstones you are correct. However, some hydro systems depended on DO as the sole source of oxygen for roots (flooded PVC tubes-no airstones Heath R. style, etc.) .Higher levels of DO also deter anaerobic organisms from living in your soup. There are plenty of reasons to be concerned with DO IMO

Roots submerged in 86F water with airstones = err, maybe
Roots submerged in 86F water/ no airstones = dead trees

 

[mike91sr]

With the addition of airstones you are correct. However, some hydro systems depended on DO as the sole source of oxygen for roots (flooded PVC tubes-no airstones Heath R. style, etc.) .Higher levels of DO also deter anaerobic organisms from living in your soup. There are plenty of reasons to be concerned with DO IMO

Roots submerged in 86F water with airstones = err, maybe
Roots submerged in 86F water/ no airstones = dead trees

Ok, I'm far from an expert on flooded tubes, but I didn't think they depended on DO for the plants to get oxygen. Any type of NFT I've personally seen has water flowing aggressively enough to be loaded with crests and bubbles, just like a fast flowing stream with rocks in it. With that said, the lower DO is again offset because there's more atmospheric oxygen than dissolved oxygen available to the roots at any given time.

Yes, high levels of DO helps aerobic and harms anaerobic, but so does total oxygen present, which makes that a moot point. Similar to high DO for oxygen uptake. Its only important if you don't have enough direct aeration.

TBH, I don't understand how you can still come to the conclusion that water at 86 is a "maybe" or complete failure when its in black and white. At least try it before you come to that conclusion since the only credible evidence out there on the subject disagrees with you. I think claiming that the extra few degrees will actually KILL a plant because less oxygen dissolves, despite a documented study proving its the MOST efficient for growth is somewhat naive. Seems we may have to agree to disagree on that one though.

 

[facestabber]

Ok, I'm far from an expert on flooded tubes, but I didn't think they depended on DO for the plants to get oxygen. Any type of NFT I've personally seen has water flowing aggressively enough to be loaded with crests and bubbles, just like a fast flowing stream with rocks in it. With that said, the lower DO is again offset because there's more atmospheric oxygen than dissolved oxygen available to the roots at any given time.

Yes, high levels of DO helps aerobic and harms anaerobic, but so does total oxygen present, which makes that a moot point. Similar to high DO for oxygen uptake. Its only important if you don't have enough direct aeration.

TBH, I don't understand how you can still come to the conclusion that water at 86 is a "maybe" or complete failure when its in black and white. At least try it before you come to that conclusion since the only credible evidence out there on the subject disagrees with you. I think claiming that the extra few degrees will actually KILL a plant because less oxygen dissolves, despite a documented study proving its the MOST efficient for growth is somewhat naive. Seems we may have to agree to disagree on that one though.

FLOODED tubes aren't NFT, they're a form of DWC. Roots stay submerged in cool, slow moving water with the sole source of oxygen for roots comes from DO. There is a direct correlation between water's temp and it's ability to absorb DO. If you really believe that 86F water is good for your roots to soak in then by all means try it and let us know how it works out. As for anyone else reading this discussion I strongly warn against it. My rez stays at 66F and I've never seen anyone with roots better than mine. I'm beginning to think this site is full of snake oil and magic sauce salesmen. Some of the advice given here is laughable and if followed will result in more problems and more $$$$ spent at the grow shop to fix them.
Maybe you could start a new thread called "How to keep your reZ as warm as bathwater" and convince people to buy aquarium heaters to cook their roots with.

 

[Warlock1369]

Not all flood tubes are like DWC. I run mine like a flood and drain system. Sence that is what my plant will get there whole life. I use tubes as a preveg. Well veg for now still working on a full veg room.

 

[mike91sr]

FLOODED tubes aren't NFT, they're a form of DWC. Roots stay submerged in cool, slow moving water with the sole source of oxygen for roots comes from DO. There is a direct correlation between water's temp and it's ability to absorb DO. If you really believe that 86F water is good for your roots to soak in then by all means try it and let us know how it works out. As for anyone else reading this discussion I strongly warn against it. My rez stays at 66F and I've never seen anyone with roots better than mine. I'm beginning to think this site is full of snake oil and magic sauce salesmen. Some of the advice given here is laughable and if followed will result in more problems and more $$$$ spent at the grow shop to fix them.
Maybe you could start a new thread called "How to keep your reZ as warm as bathwater" and convince people to buy aquarium heaters to cook their roots with.

Not sure why you went from a civilized debate to an ad hominem argument but Im done discussing this with you because of it. Youre just standing there with your eyes and ears closed screaming "IM RIGHT" over and over, repeating the same DO comment that is irrelevant since apparently winning what you for some reason believe is a pissing contest is the most important thing here. And I have no desire to sit here and try to convince you of something that you clearly are more interested in defending than understanding even though I'm not the one who ran the experiment and have no personal interest in whether or not you believe a FACT to be true, so youre defending yourself to the wrong guy. But if/when you actually want to understand it, just read the ONLY peer-reviewed information in this thread (the very stuff you're saying is wrong). And if you still want to argue it, argue with them. I'm sure your nice roots will change the minds of graduate degree holding lab rats with government-funded experiments... Deny the results/facts and tout your own successes as evidence to the contrary all you want, just makes you look even more ignorant. Later.

 

[facestabber]

Not sure why you went from a civilized debate to an ad hominem argument but Im done discussing this with you because of it. Youre just standing there with your eyes and ears closed screaming "IM RIGHT" over and over, repeating the same DO comment that is irrelevant since apparently winning what you for some reason believe is a pissing contest is the most important thing here. And I have no desire to sit here and try to convince you of something that you clearly are more interested in defending than understanding even though I'm not the one who ran the experiment and have no personal interest in whether or not you believe a FACT to be true, so youre defending yourself to the wrong guy. But if/when you actually want to understand it, just read the ONLY peer-reviewed information in this thread (the very stuff you're saying is wrong). And if you still want to argue it, argue with them. I'm sure your nice roots will change the minds of graduate degree holding lab rats with government-funded experiments... Deny the results/facts and tout your own successes as evidence to the contrary all you want, just makes you look even more ignorant. Later.

OK Mike, let me clarify. I don't disagree with the link you provided or most of what you are saying. I realize that a warm ROOT ZONE can accelerate growth IF the roots have access to adequate oxygen. My simple point is that not every form of hydroponics incorporates a froth of bubbles in direct contact with the roots. Even flood and drain systems commonly have flood times of 30+ minutes which would be detrimental if your water was at 86 degrees without an airstone in every pot. I apologize to you if I seem stubborn at times, I just don't want anyone who depends on their plants for medicine to stew their roots. Do you keep your rez at 86F? If so can you please post some root pics? (the very stuff I am saying is right, take it to the bank)

 

[waterdawg]

Jeez Mike I gotta say I'm impressed with how you bent the evaporator into the tank without kinking all of the tubes. I am a refrigeration mechanic and I would have a hell of a time accomplishing that. Also you must be running an really high head pressure as the evap coil helps to cool and condense the refrigerant in the condenser. Can you take a couple of pics of the actual unit? what is the actual temp of the water in the tank?

 

[facestabber]

Jeez Mike I gotta say I'm impressed with how you bent the evaporator into the tank without kinking all of the tubes. I am a refrigeration mechanic and I would have a hell of a time accomplishing that. Also you must be running an really high head pressure as the evap coil helps to cool and condense the refrigerant in the condenser. Can you take a couple of pics of the actual unit? what is the actual temp of the water in the tank?

The real burning question is why does Mike use a makeshift chiller when he believes that his roots would be better of cooking in 86 degree soup. Put your money where your mouth is Mike, put that aquarium heater in your rez instead!

 

[mike91sr]

Jeez Mike I gotta say I'm impressed with how you bent the evaporator into the tank without kinking all of the tubes. I am a refrigeration mechanic and I would have a hell of a time accomplishing that. Also you must be running an really high head pressure as the evap coil helps to cool and condense the refrigerant in the condenser. Can you take a couple of pics of the actual unit? what is the actual temp of the water in the tank?

Fiiiine....lol here ya go. Had to pull it out to rewire the tank killswitch on it anyway. Put it into 76F water, this is ~20 minutes later. That diagram isn't mine and my bends aren't nearly as drastic. Flipped it ~120* out and 90* down.

OK Mike, let me clarify. I don't disagree with the link you provided or most of what you are saying. I realize that a warm ROOT ZONE can accelerate growth IF the roots have access to adequate oxygen. My simple point is that not every form of hydroponics incorporates a froth of bubbles in direct contact with the roots. Even flood and drain systems commonly have flood times of 30+ minutes which would be detrimental if your water was at 86 degrees without an airstone in every pot. I apologize to you if I seem stubborn at times, I just don't want anyone who depends on their plants for medicine to stew their roots. Do you keep your rez at 86F? If so can you please post some root pics? (the very stuff I am saying is right, take it to the bank)

The real burning question is why does Mike use a makeshift chiller when he believes that his roots would be better of cooking in 86 degree soup. Put your money where your mouth is Mike, put that aquarium heater in your rez instead!

Which is it man? Do you want to have a discussion or try and burn me? Let ME clarify, you seem to be forgetting how I started this discussion. I DO NOT recommend anyone run their reservoir at 86, never said I believe my roots would be better off, just that the plant will have the potential to grow faster if everything else is equal (please no strawman fallacy, it just makes me have to repeat myself PROPERLY instead of moving forward with the discussion). HOWEVER it should be understood that for every degree lower than 86 you get, you lose growth rate potential. I even stated I run mine low 70s DESPITE knowing that a higher temp would mean a faster growth rate for the same reason most everyone does, bacteria outbreaks.

I wasn't trying to argue that there aren't methods that require more DO. Flooded tubes the way I've always seen them(including heaths) are more NFT-based than they are DWC. They can be designed either way, so yes youre right if you CHOOSE to make a dwc-style tube setup and not include airstones or waterfalls, you'll need DO. BUT to design one that needs DO when you can create more direct oxygen via faster water flow seems like an inefficient design to me. Do you agree?

I disagree with the E&F/E&G part. (I swear, Im not disagreeing just for the sake of it) I've had 3' plants submerged in non-aerated water (and not previously aerated so no residual DO) for several hours with no issues. No, it wasn't 86F more like ~75F but if they can survive several hours without wilting, I'm fairly confident they'll be okay for 30 minutes at a higher temp. Going back to what I asked about the flooded tube inefficiency, why not just reduce flood times to allow for higher temp if there ever was an issue? Again, seems like a way to boost efficiency.

Either way, I feel like that's splitting hairs and finding exceptions to the rule, avoiding the bigger point and the question I'd like to collectively address: How do we gain the benefit of faster growth that comes with higher temps, without the dangers that come with a warm hydroponic reservoir?

Bacteria are more active as a whole at higher temperatures, but the bacteria we WANT will be overrun by those we dont at those temperatures, no matter the oxygen level. So even though we can provide more than enough direct aeration to not even need DO for them to survive, its the TEMPERATURE itself that is the bacteria issue, not oxygen. I guess my other main question is: If we can control bacteria, slimes, etc at 86F, and we agree that requiring DO instead of relying on atmospheric oxygen is an inefficiency in design, can you think of another reason NOT to do it?

 

[facestabber]

Fiiiine....lol here ya go. Had to pull it out to rewire the tank killswitch on it anyway. Put it into 76F water, this is ~20 minutes later. That diagram isn't mine and my bends aren't nearly as drastic. Flipped it ~120* out and 90* down.

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Which is it man? Do you want to have a discussion or try and burn me? Let ME clarify, you seem to be forgetting how I started this discussion. I DO NOT recommend anyone run their reservoir at 86, never said I believe my roots would be better off, just that the plant will have the potential to grow faster if everything else is equal (please no strawman fallacy, it just makes me have to repeat myself PROPERLY instead of moving forward with the discussion). HOWEVER it should be understood that for every degree lower than 86 you get, you lose growth rate potential. I even stated I run mine low 70s DESPITE knowing that a higher temp would mean a faster growth rate for the same reason most everyone does, bacteria outbreaks.

I wasn't trying to argue that there aren't methods that require more DO. Flooded tubes the way I've always seen them(including heaths) are more NFT-based than they are DWC. They can be designed either way, so yes youre right if you CHOOSE to make a dwc-style tube setup and not include airstones or waterfalls, you'll need DO. BUT to design one that needs DO when you can create more direct oxygen via faster water flow seems like an inefficient design to me. Do you agree?

I disagree with the E&F/E&G part. (I swear, Im not disagreeing just for the sake of it) I've had 3' plants submerged in non-aerated water (and not previously aerated so no residual DO) for several hours with no issues. No, it wasn't 86F more like ~75F but if they can survive several hours without wilting, I'm fairly confident they'll be okay for 30 minutes at a higher temp. Going back to what I asked about the flooded tube inefficiency, why not just reduce flood times to allow for higher temp if there ever was an issue? Again, seems like a way to boost efficiency.

Either way, I feel like that's splitting hairs and finding exceptions to the rule, avoiding the bigger point and the question I'd like to collectively address: How do we gain the benefit of faster growth that comes with higher temps, without the dangers that come with a warm hydroponic reservoir?

Bacteria are more active as a whole at higher temperatures, but the bacteria we WANT will be overrun by those we dont at those temperatures, no matter the oxygen level. So even though we can provide more than enough direct aeration to not even need DO for them to survive, its the TEMPERATURE itself that is the bacteria issue, not oxygen. I guess my other main question is: If we can control bacteria, slimes, etc at 86F, and we agree that requiring DO instead of relying on atmospheric oxygen is an inefficiency in design, can you think of another reason NOT to do it?

Seems that the best method for harnessing the power of warmth for root growth without becoming overrun with bacteria would be aeroponics. I run flood and drain buckets so even though my REZ temp is 66F, my average ROOT ZONE temp would be closer to the ambient temp of the room (74F) which does give the roots some warmth. However, I still believe that a cool REZ is the way to go. Airstones and waterfalls are great if you have bubbles in direct contact with roots OR if your water is cold enough to absorb DO. Thanks for the in depth responses Mike, you make some valid points and seem to have alot to offer. Oh, and what do you think about replacing the 5 gallon bucket on your chiller setup with an igloo cooler for efficiency?

 

[legallyflying]

I'm with Mike. DIY dehu chiller. My 70 pint dehu is = 1 hp chiller and for $100. I also hard wired it to a temperature sensor...some commercial kind where you can set the temp and the temperature drift before it turns on.

Automation bitch!!

Set it, and fucking forget it.

 

[ASMALLVOICE]

If I may pose a scenario to the use of copper and/or other metal lines in a reservior. I would stay away from anything other than stainless or a higher grade aluminum, not really sure about the aluminum though. Copper, brass, and worst of all bronze, all will have a reaction to the solution in your reservior and could possibly have detrimental effects on the plants or the end users. I use a tube of 1/2" stainless, that uses regular cold tap water running thru it with a stat and a small motor actuated valve. I can keep my res. at whatever temp I set the stat for. Please note, I am a rookie grower, but I am a veteran environmental control technician and I am very familiar with chillers, boilers and what it takes to keep it going, and water treatment is one of the more serious aspects of HVAC. Chemicals such as fertilizers react on certain metals very quickly and could be toxic and make its way into your crop. I humbly ask you to do some research on metal reactivity to chemicals and keep those metals out of the reservior. If you stay with stainless steel, it leaves alot less to worry about.

Peace and Big Buds for All!

Asmallvoice

 

[waterdawg]

I'm researching the copper issue as we speak, I know geothermal systems use copper nickel heat exchangers. should have more info tonight.

 

[legallyflying]

no need to really research it bud, passing nutrient solution at the proper PH for growing will leach copper into the solution and your plants will die. Stainless steel wort chiller is what you need. best prices are on e-bay.

I bent the cooling cooling radiator from my dehumidifier into a cooler full of water. This cold water is pumped through the wort chiller that sits in the rez. It costs money, but far less than a commercial chiller and it uses the physics of phase change to cool (just like an AC) which is the most efficient means to cool something.

You can utilize a stainless steel coil on geothermal systems.