Easy DIY Homemade water chiller for RDWC

So I've been doing this recirculating grow for about 2 months now and I decided to add in a 400 watt HPS for that extra boost of light that I wanted. More light = Higher temps for me. My temps got into the 77-80 degree range constantly and even though my water was moving and I have PLENTY of air going into the bucket, I still became a victim of early sings of pythium.

So I start googling and searching through the forums looking for DIY chillers, and smaller professionally made ones online and I see a lot of great home made ones that can be done with a wine chiller or mini fridge etc.

But I didn't want to go buy a mini fridge and run the extra watts, and didn't want to really disassemble anything (Im not that great with that sort of stuff) so I thought of a quick simple way to make a homemade chiller for a recirculating system! This will chill about 5-7 gallons of water 10 degrees below ambient temperature for about 24 hours before it needs to be refilled.

*ALSO* The way my system is set up I have a 3.5 gallon RES that pumps my soup into a drip ring, where it falls down into my 5 gallon bucket that has my roots, and gets recirculated back into the 3.5 gallon and so on........ So I'm sure you can make this chiller work with any system but I will be showing you how I hooked it up to mine Very similar to this model just the water gets put into a drip ring over a much larger net pot rather than directly into the bucket.





First off go buy a styrofoam cooler from walmart. Mine ran me 2 bucks.




Then you're gonna need to grab some longer tubing that fits your submersible air pump. Mine was 1/2 inch.



Once you have your tubing its time to head over to Lowes or Home depot and grab some COPPER tubing this time. I went with the 3/8 inch cause it was cheaper I just bought some 1/2 to 3/8 adapters that work quite well! I got about 10 feet for mine but the more you get the colder your water will be!








Now you can either go freeze up about 5-10 water bottles or go buy a couple of bags of ice for a few bucks. Either way you're going to need a constant supply of these daily so just make sure to have the equivalent amount in your freezer when you need to swap them out!




The next step is to fill up your styrofoam cooler about 50% of the way with cold water.

Next you are going to want to run your tubing from your pump into the cooler, as well as running another line from inside the cooler out into the drip ring (or wherever your cycling your water.)





Finally submerge the copper tubing in the cold water and cover it with as much ice cold water bottles or bags of ice as you can! Then connect both ends into the poly tubing with the adapters.





Plug in your pump and let it circulate! Mine lowers my temperatures in a matter of minutes. I hope a lot of people who cannot simply afford a chiller at the moment or are like me and only have a single bucket that they need to chill. This has no mechanical parts and works quite well as long as you refill it

I ended up just buying a 25 dollar cooler from walmart its bigger and holds more water and ice for days at a time but I gotta be careful now cause it was getting my water in the low 50's which I don't want them to get that low just an average of around like 68 degrees F

so I hooked it up to a timer and I have it running of half an hour every 2 hours as of right now

I thought that copper was bad to have nutrients passing through. I would search that in case of any issues.
Still a great job and low cost. But that's the reason I didn't go this route.

S13hitman said:

I thought that copper was bad to have nutrients passing through. I would search that in case of any issues.
Still a great job and low cost. But that's the reason I didn't go this route.

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Yep

Tone5500 said:

Yep

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well dang I didn't think of that I searched its little and read copper is essential to plant life so I didn't know if a small bit like this would hurt too much. thank you for the info

do you think it would be better have a higher temp res 77-80, or to have a 65 degree constant res that uses the copper tubing... which would do more harm you think?

PatchKid said:

well dang I didn't think of that I searched its little and read copper is essential to plant life so I didn't know if a small bit like this would hurt too much. thank you for the info

do you think it would be better have a higher temp res 77-80, or to have a 65 degree constant res that uses the copper tubing... which would do more harm you think?

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Use stainless steel I think ppl use wort chiller for beer

I used to freak out about the res temps all the time in my RDWC and used frozen bottles, etc, etc. But the res temp is not as big of an issue if you follow some key steps. My RDWC has res temps reaching the high 70s during the summer and I have never had issues.

But there are a couple KEY things to be successful with warmer res temps.

First, and most importantly, you need to be using beneficial bacteria from the very start and renewing it with every res change. I use SubCulture-B baccillus root inoculant from GH. Using beneficial makes your roots happy and makes it MUCH harder for the slime to take hold.

Second, you need to keep your res super aerated. This not only keeps the bennys happy and healthy along with your root system, it does help cool the res some too. Try to place your air pump(s) away from the lights and low to the ground, where the air temps will be coolest.

Lastly, use a control bucket and again keep it a few feet away from lights. This will help dissipate some of the heat as well. I use a tent grow and keep my control OUTSIDE. This makes a huge difference.

But remember, if your entire room is 85deg+, you will never get your res temps down. It's much easier to cool the room and dissipate heat into the env than it is to chill the water in a hot room (which is losing battle).

In my experience, this works. I stopped using ice bottles a couple years ago and never looked back.

Good luck!

diggabyte said:

I used to freak out about the res temps all the time in my RDWC and used frozen bottles, etc, etc. But the res temp is not as big of an issue if you follow some key steps. My RDWC has res temps reaching the high 70s during the summer and I have never had issues.

But there are a couple KEY things to be successful with warmer res temps.

First, and most importantly, you need to be using beneficial bacteria from the very start and renewing it with every res change. I use SubCulture-B baccillus root inoculant from GH. Using beneficial makes your roots happy and makes it MUCH harder for the slime to take hold.

Second, you need to keep your res super aerated. This not only keeps the bennys happy and healthy along with your root system, it does help cool the res some too. Try to place your air pump(s) away from the lights and low to the ground, where the air temps will be coolest.

Lastly, use a control bucket and again keep it a few feet away from lights. This will help dissipate some of the heat as well. I use a tent grow and keep my control OUTSIDE. This makes a huge difference.

But remember, if your entire room is 85deg+, you will never get your res temps down. It's much easier to cool the room and dissipate heat into the env than it is to chill the water in a hot room (which is losing battle).

In my experience, this works. I stopped using ice bottles a couple years ago and never looked back.

Good luck!

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Thanks for the awesome reply!!! Yes I used bennies before they work great! I guess this is more for people who run a sterile res !

No problem.

And keep in mind, I am not talking about organic tea bennies or anything dirty like that. It's just a few hundred milligrams of powder with each res change.

A true 'sterile' res is impossible outside of laboratory conditions. Bacteria will grow, period. The temperature affects which type of bacteria grows and how quickly it grows. Even at 68F, your res water will be teeming with bacteria.

Pythium just prefers warmer temps.

Sweet! Will def keep that in mind My res stays 66 degrees and stays getting slammed with o2 and gets Dutch master zone routine and roots are pearls with extremely good growth

Looking into Heisenberg tea

I use hydroguard and my Rez temp stays at 75 never a problem this lets me keep my room temps a little higher were my plants thrive only bad thing is hydroguard only has a six month life after being opened

I've been using water chilling for cooling RDWC water and controlling environments for years now. All the ice chest gizmo has really done is transfer the cost of operating the refrigeration equipment from a chiller to your freezer or the ice maker's equipment. If that's economical, fine. But what if there was a better alternative?

I built a compressorless water chiller from a car radiator, its fan shroud and a box fan. This system uses the cold temperatures outside in the Colorado winter to effectively chill my entire op, soup to nuts.

Tone5500 said:

I use hydroguard and my Rez temp stays at 75 never a problem this lets me keep my room temps a little higher were my plants thrive only bad thing is hydroguard only has a six month life after being opened

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nice man that's awesome, I've heard good things about hydro guard, it was an ingredient in that Heisenberg tea I mentioned as well. Since my res can chill all the way down to like the mid 50's the temps in my room really don't have that much of an effect at all on the root zone

ttystikk said:

I've been using water chilling for cooling RDWC water and controlling environments for years now. All the ice chest gizmo has really done is transfer the cost of operating the refrigeration equipment from a chiller to your freezer or the ice maker's equipment. If that's economical, fine. But what if there was a better alternative?

I built a compressorless water chiller from a car radiator, its fan shroud and a box fan. This system uses the cold temperatures outside in the Colorado winter to effectively chill my entire op, soup to nuts.

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that's pretty dope but you have to think about people who aren't as good at stuff like that lol. I'm using a singe 5 gallon bucket man that would be way too much and this system is completely electric free doesn't heat up the water at all like pumps do and you only have to change out the water bottles every other day or so (if you're growing hydro you better be paying attention daily) and I don't have to worry about anything going out or not working

plus it was like 30 bucks for this setup

PatchKid said:

nice man that's awesome, I've heard good things about hydro guard, it was an ingredient in that Heisenberg tea I mentioned as well. Since my res can chill all the way down to like the mid 50's the temps in my room really don't have that much of an effect at all on the root zone




that's pretty dope but you have to think about people who aren't as good at stuff like that lol. I'm using a singe 5 gallon bucket man that would be way too much and this system is completely electric free doesn't heat up the water at all like pumps do and you only have to change out the water bottles every other day or so (if you're growing hydro you better be paying attention daily) and I don't have to worry about anything going out or not working

plus it was like 30 bucks for this setup

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You ever switch out that copper tubing

Tone5500 said:

You ever switch out that copper tubing

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no I never did and here is the plant in the picture about 2 weeks later looks healthy to me

PatchKid said:

no I never did and here is the plant in the picture about 2 weeks later looks healthy to me

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Looks good but what it does is leach into the plant creating a toxic smoke at least that's what my understanding was of it.. Nice plant tho how often you gotta change out that ice ???

Tone5500 said:

Looks good but what it does is leach into the plant creating a toxic smoke at least that's what my understanding was of it.. Nice plant tho how often you gotta change out that ice ???

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the cooler that I use is rated to keep ice frozen for 5 days under 90 degree temps. I chsnge out my water bottles ever other couple of days cause the holes I have drilled for the tubing aren't sesled yet so heat gets in but it still works great

The compressorless chiller is not a complicated build and does not need to be fed ice on a regular basis. This makes it at least as simple and a lot cheaper than your solution- at least in cold weather.

Kicking this idea up a notch brings us to heat pumps, which can pull the heat from your grow op and reuse it to heat your home and even domestic hot water. Now that's saving energy!

Using copper heat exchange coils in the nutrient reservoir is NOT a problem, unless you like running your pH down strong enough to strip metal corrosion.

The molarity- acidic strength- needs to be MUCH higher before leaching copper from tubing becomes an issue.

I've been running these for years and the only time I got copper toxicity was from badly mixed nutes from the mfr.

Myth: BUSTED.

Hey patch! As my grow room is air conditioned, do you think that running a separate res outside of the closet (closer to the 25 Celsius that I run the room) would lower the overall temp enough?