DIY RDWC Question

Indoor Growing Hydroponics
#1

I live in a hot, humid area, and it’s dead middle of summer. I have had problems with root rot unless I chill my water somehow. I have a big mini fridge that gets so cold it freezes water completely. I was thinking about making a stainless steel wort chiller, dropping the coils in a metal stockpot of water, and running it through the mini fridge from and back to my reservoir to cool my RDWC nutrient solution. I was thinking about 25 feet of 3/8 tubing, but I’m not sure what size water pump. Would this be effective for 15-20 gallons of nutrients? My reservoir and containers my plants go in are insulated with great stuff foam, and covered with Mylar (no Mylar on reservoir it’s outside grow area). Anyone tried this or have any suggestions?
I was thinking the nutes would cool quickly because of the metal transferring temperature, and the water around the tubing would be frozen in a day or two. So, I hope it would be effective in keeping my root temps down.

*I have had success using frozen milk jugs, but got tired of switching and cleaning them. I had used about 30 foot of polyethylene tubing coiled in a plastic container and then put inside a mini fridge before, and it worked pretty well. But last time I had hell with the water pump pushing it through the coils and back into my reservoir. I think it was kinked somewhere I couldn’t see.

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#2

@WhiteHotAfterburner made a chiller from an old water cooler. @JoeCrowe is a DWC guru. Maybe one if them have some thoughts.

:+1::seedling:

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#3

I don’t see why it shouldn’t work good . Just the plumbing and water pump parts to figure out . I’d maybe go with a low flow pump the more time it spends cooling in the fridge the colder it should get.

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#4

Not quite the same, but check out this thread as well:

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#5

You could get a cheap, used window ac and use the evap coils (cold side) to chill water. You’d need a way to supply air, and remove the heat from the condenser though. If you wanted to have that setup in the same room.

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#6

“Oxygen content of a fully aerated solution at 10C (50 F) is about 13ppm, but as the
solution warms up to 20C (68 F) the ability of the liquid to `hold’ oxygen drops to 9 -
10ppm, by the time the solution has reached 30C (86 F), then it’s only 7ppm.”
The study goes on to talk about the side effects of low oxygen levels in terms of nutrient problems and pathogen growth. I would say temperature is integral to the operation, and my whole lab is constructed to help manage it with heat extraction and 16C floors.

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#7

So what temp do you aim to hit?

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#8

I try to hit 18C but I am ok with 20C, but nothing higher.

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#9

So you plan on using a coil in a pot of water sticking that in the cooler and cycling the nutrient solution through the tubing? That would work. Id use some armaflex on the tubing as it exits the cooler to prevent sweating and adding excess humidity to your room.

As far as a pump goes something around 500GPM should suffice.

I have had good results up to 75F, but youre rolling the dice anything over 70F

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#10

Arent those copper? Copper is a poor material to use for nutrient solutions as it leaches copper from the pipes.

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#11

Yes.
You use the ac evap coils to chill a cooler or similar full of water, and you use that chilled water to pump out to wort chiller coils in the actual reservoirs, remotely.

Also, you could put the evap coils in a bag instead. It’s not elegant but it works. Coating them with plasti-dip or something kinda insulates them too much.

#12

perhaps aluminum instead of copper?

Cheers
G

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#13

Welcome back! long time no see! @Hustlynn
:green_heart: :seedling: