Any recommendations for keeping down water temps?

[SkinnieP]

Hey guys. New grower trying to get my grow tent environment dialed in. I've got pretty much everything covered aside from water temps. And what would be an easy solution for someone running a bigger system, my system is very small. I have 2 separate 5 gallon bucket DWC systems in a 2x2x72 tent. (Yes I know that's crowded but I'm keeping both girls alive for now because I am new and want an insurance policy in case one bites the dust)

Only problem is, it's getting a little too hot. The air temp in the tent gets to be about 79 degrees, which I think means the water temps are teetering right in the danger zone for root rot.
I'm have my inline fan programmed to take care of other parameters, so I can't re-assign it for the temperature.

I think possibly the best option would be to get a small water chiller or very small AC unit? Either that or shuttle in ice cubes every couple hours which seems a little stupid for the long term. lol.

What do you guys use to keep your water temps down, or what would you use to keep the water temps down? Appreciate your input <3

 

[steamroller]

Many use chillers but they ain't cheap.
Active Aqua chillers have been brought up here before as a good chiller.
For just 1 or 2 plants a 1/10 HP chiller would work.
About $400 for active aqua compared to $250 for off brand.

 

[SkinnieP]

Many use chillers but they ain't cheap.
Active Aqua chillers have been brought up here before as a good chiller.
For just 1 or 2 plants a 1/10 HP chiller would work.
About $400 for active aqua compared to $250 for off brand.

Geez man. Price is important but not the main issue.. Would an active aqua chiller work for 2 separate 5 gallon dwc systems? Or would I have to get two active aqua chillers? I'm just very unfamiliar with this stuff so I appreciate any and all feedback. Thank you

 

[steamroller]

To run both buckets it would be best if they were connected to each other like a recirculating system so all the water could flow through the chiller.
IMO it would be a headache to hook up two separate buckets to one chiller. A good handle on custom plumbing would be real handy.
Chillers do not come with circulation pumps so the recirculating systems are more properly built to have a chiller hooked up inline.

 

[GoodShit97]

Geez man. Price is important but not the main issue.. Would an active aqua chiller work for 2 separate 5 gallon dwc systems? Or would I have to get two active aqua chillers? I'm just very unfamiliar with this stuff so I appreciate any and all feedback. Thank you

It may be better to convert that 2 bucket dwc system to a 2 bucket RDWC system.

Ive seen people use frozen bottles of water too but idk how long they last or if it'll work in buckets like that.

 

[GrumpAzz]

Geez man. Price is important but not the main issue.. Would an active aqua chiller work for 2 separate 5 gallon dwc systems? Or would I have to get two active aqua chillers? I'm just very unfamiliar with this stuff so I appreciate any and all feedback. Thank you

I would think a 1/10 would be sufficient. That's what I have. Active Aqua brand. It takes care of my whole system that has ~18 gallons in it. I plan on using it for my next run that will be a 4 site system. It hardly runs as it is now, so I'm confident it can handle more. Pricey little unit but it's been worth it's weight in gold.

Like Steam said, you'll have to get a little creative to run two separate buckets off of one chiller. Not impossible and pretty easy to do. You'll just have to play around with a couple ideas. You're breaking into R-DWC territory at that point.

 

[GoodShit97]

So many people praise active aqua pumps. Definitely the route I'll be taking if I ever go hydro, regardless of the price. When so many people in the community back a certain company, I could care less what the price is as long as its damn good lol.

 

[moe.red]

Another vote for Active Aqua. I have 3 of the 1/4 that are probably getting in the 6 - 8 years old range, still going strong.

It's a set it and forget it kinda thing.

Just to be clear tho, higher temp does not equal root rot. As temps go up, so does microbial activity across the board. So if you have good bacteria in there, it actually does a bit better in the mid 70s. The issue is with O2 concentrations. Lower temp = more O2. Dissolved O2 is one of the roadblocks or limiting factors to getting plants to the next level. I'm gonna find a pic and edit this.

Edit: this is a plant grown at higher temps (75 ish) but injecting 90% O2

 

[SpectrumFarms]

It may be better to convert that 2 bucket dwc system to a 2 bucket RDWC system.

Ive seen people use frozen bottles of water too but idk how long they last or if it'll work in buckets like that.

I started growing in DWC and I’m in a hot climate. I used water bottle, ice packs etc. they worked as long as you can change them out every couple of hour. I switched to coco, where I’m at it almost seems necessary to have a chiller.

 

[GoodShit97]

I started growing in DWC and I’m in a hot climate. I used water bottle, ice packs etc. they worked as long as you can change them out every couple of hour. I switched to coco, where I’m at it almost seems necessary to have a chiller.

Water and I don't get along.
I bet ya I couldn't even grow water lilies...
I'm a dirt farmer lol

 

[SkinnieP]

Another vote for Active Aqua. I have 3 of the 1/4 that are probably getting in the 6 - 8 years old range, still going strong.

It's a set it and forget it kinda thing.

Just to be clear tho, higher temp does not equal root rot. As temps go up, so does microbial activity across the board. So if you have good bacteria in there, it actually does a bit better in the mid 70s. The issue is with O2 concentrations. Lower temp = more O2. Dissolved O2 is one of the roadblocks or limiting factors to getting plants to the next level. I'm gonna find a pic and edit this.

Edit: this is a plant grown at higher temps (75 ish) but injecting 90% O2

View attachment 60552

Dang buddy those roots look CLEAN

 

[moe.red]

Dang buddy those roots look CLEAN

Here's a cut and paste quick explanation of why O2 matters in the root zone.






Photosynthesis and respiration are the two main plant growth processes that are key to healthy plants and quality crops.

Figure 1: Image from Khanacademy.org


During photosynthesis, leaves and stem cells use solar energy to combine carbon dioxide (CO2) from the air with water absorbed through root cells to make sugar in the form of glucose. This glucose is used for many metabolic processes in all parts of the plant, including the production of cellulose and starch.

Glucose is also a critical fuel source for root cell respiration, a process that’s basically the opposite of photosynthesis.

In respiration, root cells burn glucose that’s been transported from the leaves. Glucose is transformed into cellular energy (called adenosine triphosphate or ATP) that’s used to drive metabolic processes, mainly water and nutrient uptake.

Figure 2: Image from Vecteezy.com

Without oxygen, respiration does not take place. Oxygen is the final electron acceptor in aerobic respiration which is essential for transforming glucose in ATP.

OXYGEN IS THE LIMITING FACTOR FOR QUALITY CROPS​

The amount of oxygen available to root cells matters for healthy plant growth rate and crop yield. Without a lot of oxygen available to them, root cells are limited in the amount of sugar they can burn and how much water and nutrients are absorbed.

Reducing a plant’s water and nutrient uptake rate directly restricts its overall growth rate and the yield and quality of its fruit. Weak plants are more susceptible to diseases and less resilient to environmental stressors, such as heat during the warmer months.




I did the red highlight. This is something that is so commonly overlooked by growers.

Those roots look all clean and sexy, but what they really are is super efficient.

 

[Observer]

Currently don't use a chiller, water gets up to 75-80f

 

[Pipecarver]

I have 1/10 hp Active Aqua chiller running 6 autopots easily. I picked mine up on Facebook market place $300. new in box..

 

[Pipecarver]

Another vote for Active Aqua. I have 3 of the 1/4 that are probably getting in the 6 - 8 years old range, still going strong.

It's a set it and forget it kinda thing.

Just to be clear tho, higher temp does not equal root rot. As temps go up, so does microbial activity across the board. So if you have good bacteria in there, it actually does a bit better in the mid 70s. The issue is with O2 concentrations. Lower temp = more O2. Dissolved O2 is one of the roadblocks or limiting factors to getting plants to the next level. I'm gonna find a pic and edit this.

Edit: this is a plant grown at higher temps (75 ish) but injecting 90% O2

View attachment 60552

Is that a temp you like to run at 75f?..I have mine set at 70f, plants seem to love it.......not sure what you think but I believe my plants like a stable water temp better than when it was fluctuating with cold nights and hot days.

 

[SpectrumFarms]

Water and I don't get along.
I bet ya I couldn't even grow water lilies...
I'm a dirt farmer lol

I’m doing some research now on soil. I’d like to try my hand at organic living soil one day. Right now I’m on team coco.

 

[moe.red]

Is that a temp you like to run at 75f?..I have mine set at 70f, plants seem to love it.......not sure what you think but I believe my plants like a stable water temp better than when it was fluctuating with cold nights and hot days.

Based on my growspace if I am injecting o2 I leave the chiller off. If standard RDWC I like 72. @Aqua Man agrees and he’s got a similar climate I think. I think @smoke and @SweetLeafGrow do 70 but correct me if I’m wrong pls

 

[moe.red]

I’m doing some research now on soil. I’d like to try my hand at organic living soil one day. Right now I’m on team coco.

Did you see the thread on Korean natural farming? If I was trying organic I’d be trying that. Really interesting and amazing results.

 

[SpectrumFarms]

Did you see the thread on Korean natural farming? If I was trying organic I’d be trying that. Really interesting and amazing results.

I did, it’s very interesting and right in my wheel house.

 

[SpectrumFarms]

Did you see the thread on Korean natural farming? If I was trying organic I’d be trying that. Really interesting and amazing results.

I did, it’s very interesting and right in my wheel house.

 

[smoke]

Based on my growspace if I am injecting o2 I leave the chiller off. If standard RDWC I like 72. @Aqua Man agrees and he’s got a similar climate I think. I think @smoke and @SweetLeafGrow do 70 but correct me if I’m wrong pls

My chilleris set at 68

 

[GrumpAzz]

My chilleris set at 68

Mine is at 71. I run a live system using Orca. So far so good.

 

[SkinnieP]

Based on my growspace if I am injecting o2 I leave the chiller off. If standard RDWC I like 72. @Aqua Man agrees and he’s got a similar climate I think. I think @smoke and @SweetLeafGrow do 70 but correct me if I’m wrong pls

So you can use a better air stone to get more bubbles, and in turn that creates more oxygen in the water.
This may be a silly question, but does more bubbles = more DO? I've read about dissolved oxygen, and you mentioned it above but I wasn't sure if that was the same as just adding more bubbles/activity to the water.

 

[GrumpAzz]

So you can use a better air stone to get more bubbles, and in turn that creates more oxygen in the water.
This may be a silly question, but does more bubbles = more DO? I've read about dissolved oxygen, and you mentioned it above but I wasn't sure if that was the same as just adding more bubbles/activity to the water.

I'm probably remembering this wrong, but I believe most of the oxygenation happens when the surface tension of the water is broken and the bubbles from the airstones don't add much until they rise and break the surface. The argument there would be more smaller bubbles or less bigger bubbles. Air stones do a better job of circulating the water by churning it up a bit. Again though... I'm probably wrong.

What I'm getting at is don't sweat the bubbles. What you have going on is fine. Your other plant doing well is evidence of that.

 

[smoke]

https://cch2o.com/wp-content/uploads/2021/08/CCH2O-AirFlow-Regulator-Instructions.pdf

 

[moe.red]

So you can use a better air stone to get more bubbles, and in turn that creates more oxygen in the water.
This may be a silly question, but does more bubbles = more DO? I've read about dissolved oxygen, and you mentioned it above but I wasn't sure if that was the same as just adding more bubbles/activity to the water.

To a point.

Vast majority of gas exchange in water happens at the surface. The surface area of a bubble and the dwell time in the water column does not add that much directly. What it does do is stir the water to bring new water to the surface, and also drives off the CO2 that is emitted thru the roots.

Having an air pump that essentially pressurizes the res makes sure that the atmosphere in the res is the same as outside. If you do not do this, you will have a build up of CO2 and a slide towards disaster.

But there are limits. If you like to research, Henry's Law is what governs the amount of gasses that can be put into water

Henry's law - Wikipedia

en.wikipedia.org

Normal DO levels in water at equilibrium at sea level are about 8mg/L. If you put plants in that water and do not actively replace the O2, it will plummet as the plant uses the O2.

The only way to get above 8mg/L is to either put the water under pressure (this can be done with aeroponics and pressure pumps driving sprayers) or by exceeding the typical 21% O2 you find in the atmosphere feeding the system.

So if you used an Oxygen Concentrator, you can see 3X the DO in the res you could ever get thru bubbling. Those are some amazingly happy plants if you do.


Short answer, there is no benefit to adding pumps and air stones if your res is at 8mg/L. It will not go any higher. If it is not there, then yes add more air.

Most growers do not have a DO meter, which makes it difficult to tell you if you need more bubbling or not. As a rule of thumb, I have found that a properly driven 2" x 4" cylinder style air stone per plant will get you to 8mg/L.

 

[moe.red]

I'm probably remembering this wrong, but I believe most of the oxygenation happens when the surface tension of the water is broken and the bubbles from the airstones don't add much until they rise and break the surface. The argument there would be more smaller bubbles or less bigger bubbles. Air stones do a better job of circulating the water by churning it up a bit. Again though... I'm probably wrong.

What I'm getting at is don't sweat the bubbles. What you have going on is fine. Your other plant doing well is evidence of that.

That's twice now in this thread we replied at the same time with the same answer. Maybe it's time for me to retire and let you handle these! I'm impressed with your sponge like learning on this stuff.

 

[GrumpAzz]

That's twice now in this thread we replied at the same time with the same answer. Maybe it's time for me to retire and let you handle these! I'm impressed with your sponge like learning on this stuff.

That's awesome, dude. I learned from the best, if you know what I mean. I retain a lot of it but I barely trust my memory these days. That's why I always add that little "I'm probably wrong" disclaimer."

 

[moe.red]

That's why I always add that little "I'm probably wrong" disclaimer.

I should probably put that in my sig line too. According to my wife, it's just understood that if my lips are moving, I'm wrong.

 

[Pipecarver]

My chilleris set at 68

I had mine at 68f for a while but my roots were off color more brownish than white when I chopped them down so I bumped it 2f this run to see if there's any difference....My plants grew fine but I didn't like the off colored roots.