Quick question on my upcoming RDWC build.

Discussion in 'Hydroponics / Aeroponics' started by TIMtoKILL, Jun 12, 2018.

  1.  
    TIMtoKILL

    TIMtoKILL Member

    Hey guys been lurking around for awhile, I just moved to a new place and finally can start up my little home project. I used to run a straight DWC 5 gallon buckets and had a heck of a time changing out Res and training the girls. Anyway to eliminate that I’ve decided to go with an RDWC system. I plan on having 2 grow buckets with an epicenter. I’m going to use an old college mini fridge to create a chiller and wanted to use an under current with the waterfall effect to eliminate the need for air stones.

    Now do I run my water pump from my epicenter/res, to my chiller, then T it off and run it to the top of both of my grow buckets to create my DO in the buckets through waterfalls. Or do I just waterfall my epicenter? And create my return line from a filter tube in my main pvc line?

    The videos that explain these always use air stones. Any links or resources you guys have would be awesome or just general advice. Thanks in advance!
     
  2.  
    Airwalker16

    Airwalker16 Well-Known Member

    If it's just 2 buckets, run from the chiller to each waterfall.a
     
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  3.  
    TIMtoKILL

    TIMtoKILL Member

    Would I also put a waterfall in my epicenter then? Thanks for the reply.
     
  4.  
    JSB99

    JSB99 Well-Known Member

    More than a few times I've read that using a mini as a chiller will quickly burn out the fridge because if how much it has to run to keep up with the constant need for heat removal.

    I switch to soil in the summer so I don't have to try and fight those summer temps.

    Check out my RDWC Build in my signature. It might help you with some ideas.

    Also, creating a waterfall(s) is only half the battle. You've got to get the dissolved oxygen, created by the waterfall(s), to the center of the root mass. For that, you need a water pump powerful enough to cycle the total water content, 12 times an hour. The pump creates enough flow to reach the center of the roots. This is why some people, like myself, also use an air pump, to help deliver the DO. The pump also creates heat, and will warm up your water.
     
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    JSB99

    JSB99 Well-Known Member

    Cycling the water content 12 times an hour is what qualifies an RDWC as an "Under Current".
     
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    Airwalker16

    Airwalker16 Well-Known Member

    No just have your return lines (1”+)be going to the reservoir bucket to gravity fill it as the pump for the chiller drains it.
     
  7.  
    Airwalker16

    Airwalker16 Well-Known Member

    If you’re on concrete, you could probably get away with no chiller at all if you use an INLINE pump to supply your waterfalls so you’re not heating things up with a submersible pump.
     
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    TIMtoKILL

    TIMtoKILL Member

    The mini fridge would be thrown away if I didn’t use it so I mind as well use it. I figured I’d try and fit 70 feet of tubing in it, should that be one inch as well? I ended up buying a 1000 gph water pump so with only 2 girls growing it should be more than enough. I also tried to look at your signature but I can’t seem to find it, I would love to look at it though. Could you possibly post a link? Thanks in advance!
     
    Last edited: Jun 13, 2018
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  9.  
    TIMtoKILL

    TIMtoKILL Member

    I have a pump that can be both, I just live in the south so I’m going to need a chiller and probably an A/c too. With a 1000 gph pump will 1” lines be enough? I was planning on going with 2” or even 3” on the return lines at the bottom.
     
  10.  
    Airwalker16

    Airwalker16 Well-Known Member

    2” will be neededwith 1000gph. You’re going to need to use a much smaller pump for your chiller though. Like 80-300gph. Whatever it tells you to use. And if you’re moving water that fast, just have the retu line of the chiller go back into the reservoir.
     
  11.  
    Airwalker16

    Airwalker16 Well-Known Member

    2” will be needed with 1000gph. And if you’re moving water that fast, just have the return line of the chiller go back into the reservoir. But you’re going to need to use a much smaller pump for your chiller though. Like 80-300gph. Whatever it tells you to use.
     
  12.  
    redi jedi

    redi jedi Well-Known Member

    Ive built a mini frigde chiller...its a fire hazard and could barely keep 30-35 gals under 75f
     
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  13.  
    JSB99

    JSB99 Well-Known Member

    Look right below and you'll see my signature box. I have the link directly under the cola pics. It's named "My RDWC/UC Grow Room".
     
  14.  
    JSB99

    JSB99 Well-Known Member

    What you want to do is find the largest container you can fit inside the fridge. Fill that with water, and put your coils in the water. Water retains temps four times longer than air, so once it's cold, it'll keep your compressor from kicking on as much. I've seen people here at RIU use used drinking fountains/water coolers as a better alternative, so if it burns out, that might be a better option. I just switch to soil in the summer. It's a much easier solution IMHO :)

    PS: You want to use stainless steel coil, also known as "wort chiller", and is used in making beer. Vinyl won't do the heat exchange well enough to cool very well, and copper leeches metal into the reservoir water (or something like that), and that's no bueno :)

    Here's a wort chiller coil
     
  15.  
    Airwalker16

    Airwalker16 Well-Known Member

    No compressor on a DIY fridge chiller buddy.
     
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    eyderbuddy

    eyderbuddy Well-Known Member

    please show? i'm a sucker for ingenious DIY
     
  17.  
    redi jedi

    redi jedi Well-Known Member

    0725112013-00.jpg
    Thats the first variant. This did nothing...except slowy start poisoning my plants. The second variant I put the coil in a 5gal bucket with water...2 deg f change. The third variant I put the icebox which has refrigerant flowing through it in the bucket with the coil which gave me 5-7 deg f change but the fridge ran constantly and got so hot the paint turned yellow and was too hot to touch. Now if I had insulated my rdwc it surely would have helped a bit but in the long run this contraption wouldn't last and possibly could have caught fire...not worth it IMO to save a couple hundred bucks.
     
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  18.  
    redi jedi

    redi jedi Well-Known Member

    All refrigeration devices have a compressor...
     
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    redi jedi

    redi jedi Well-Known Member

    This is rdwc I was trying to cool under 2k hps
    0725112011-00.jpg
     
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  20.  
    JSB99

    JSB99 Well-Known Member

    Yeah, if you don't remove the heat from the room, it won't do a thing. You'd have to either have the fridge in another room, or build an insulated box around the fridge, with an inline fan to duct the heat somewhere else.
     

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